  United States Court of Appeals
      for the Federal Circuit
                 ______________________

 RICHARD A. WILLIAMSON, Trustee for At Home
       Bondholders Liquidating Trust,
              Plaintiff-Appellant,

                            v.

  CITRIX ONLINE, LLC, CITRIX SYSTEMS, INC.,
       MICROSOFT CORPORATION, AND
           ADOBE SYSTEMS, INC.,
             Defendants-Appellees,

                          AND

WEBEX COMMUNICATIONS, INC., CISCO WEBEX,
       LLC, AND CISCO SYSTEMS, INC.,
             Defendants-Appellees,

                          AND

     INTERNATIONAL BUSINESS MACHINES
              CORPORATION,
              Defendant-Appellee.
            ______________________

                       2013-1130
                 ______________________

   Appeal from the United States District Court for the
Central District of California in No. 11-CV-2409, Judge A.
Howard Matz.
                    ______________________
2                          WILLIAMSON   v. CITRIX ONLINE, LLC



               Decided: November 5, 2014
                ______________________

    BRETT J. WILLIAMSON, O’Melveny & Myers LLP, of
Newport Beach, California, argued for plaintiff-appellant.
With him on the brief was TIMOTHY D. BYRON. Of counsel
on the brief were WILLIAM NORVELL, JR., SCOTT D. MARRS
and BRIAN THOMAS BAGLEY, Beirne, Maynard & Parsons,
L.L.P., of Houston, Texas.

    KURT L. GLITZENSTEIN, Fish & Richardson P.C., of
Boston, Massachusetts, argued for all defendants-
appellees. With him on the brief for defendants-appellees
Citrix Online, LLC, et al. were FRANK E. SCHERKENBACH,
of Boston, Massachusetts; and INDRANIL MUKERJI, of
Washington, DC. Of counsel was Jonathan J. Lamverson,
of Redwood City, California. On the brief for defendants-
appellees Webex Communications, Inc., et al. were
DOUGLAS M. KUBEHL, SAMARA L. KLINE and BRIAN D.
JOHNSTON, Baker Botts LLP, of Dallas, Texas. On the
brief for defendant-appellee International Business Ma-
chines Corporation were MARK J. ABATE and CALVIN E.
WINGFIELD, JR., Goodwin Procter LLP, of New York, New
York, GREGORY S. BISHOP, of Menlo Park, California, and
WILLIAM F. SHEEHAN, of Washington, DC. Of counsel was
ISABELLA E. FU, Microsoft Corporation, of Redmond,
Washington, for defendant-appellee Microsoft Corpora-
tion.
                 ______________________

    Before MOORE, LINN, and REYNA, Circuit Judges. 1



    1   Randall R. Rader, who retired from the position of
Circuit Judge on June 30, 2014, did not participate in this
decision. Judge Moore was appointed to join the panel
pursuant to Fed. Cir. R. 47.11.
WILLIAMSON   v. CITRIX ONLINE, LLC                       3



    Opinion for the court filed by Circuit Judge LINN.
    Dissenting opinion filed by Circuit Judge REYNA.
LINN, Circuit Judge.
    Richard A. Williamson (“Williamson”), as trustee for
the At Home Corporation Bondholders’ Liquidating Trust,
owns U.S. Patent No. 6,155,840 (“the ’840 patent”) and
appeals from the stipulated final judgment in favor of
defendants Citrix Online, LLC; Citrix Systems, Inc.;
Microsoft Corporation; Adobe Systems, Inc.; Webex Com-
munications, Inc.; Cisco Webex, LLC; Cisco Systems, Inc.;
and International Business Machines Corporation (collec-
tively, “Appellees”). Because the district court erroneous-
ly construed the limitations “graphical display
representative of a classroom” and “first graphical display
comprising . . . a classroom region,” we vacate the judg-
ment of non-infringement of claims 1–7 and 17–24 of
the ’840 patent. Because the district court erroneously
construed the limitation “distributed learning control
module,” as a means-plus-function expression, we vacate
the judgment of invalidity of claims 8–12 of the ’840
patent under 35 U.S.C. § 112, para. 2. Accordingly, we
remand.
                        BACKGROUND
                     I. The ’840 Patent
     The ’840 patent describes methods and systems for
“distributed learning” that utilize industry standard
computer hardware and software linked by a network to
provide a classroom or auditorium-like metaphor—i.e., a
“virtual classroom” environment. The objective is to
connect one or more presenters with geographically
remote audience members. ’840 patent, col. 2 ll. 10–14.
The disclosed inventions purport to provide “the benefits
of classroom interaction without the detrimental effects of
complicated hardware or software, or the costs and incon-
4                           WILLIAMSON   v. CITRIX ONLINE, LLC



venience of convening in a separate place.” Id. at col. 2 ll.
4–7.
    There are three main components of the “distributed
learning” system set forth in the ’840 patent: (1) a pre-
senter computer, (2) audience member computers, and (3)
a distributed learning server. The distributed learning
server implements a “virtual classroom” over a computer
network, such as the Internet, to facilitate communication
and interaction among the presenter and audience mem-
bers. The presenter computer is used by the presenter to
communicate with the audience members and control
information that appears on the audience member’s
computer screen. Id. at col. 4 l. 66–col. 5 l. 2. An audi-
ence member’s computer is used to display the presenta-
tion and can be used to communicate with the presenter
and other audience members. Id. at col. 5 ll. 11–14.
    The ’840 patent has three independent claims. These
claims recite the following:
    1. A method of conducting distributed learning
    among a plurality of computer systems coupled to
    a network, the method comprising the steps of:
       providing instructions to a first computer sys-
    tem coupled to the network for:
            creating a graphical display representative
        of a classroom;
            creating a graphical display illustrating
        controls for selecting first and second data
        streams;
             creating a first window for displaying the
        first selected data stream; and
            creating a second window for displaying
        the second selected data stream, wherein
WILLIAMSON   v. CITRIX ONLINE, LLC                       5



          the first and second windows are dis-
      played simultaneously; and
       providing instructions to a second computer
   system coupled to the network for:
           creating a graphical display representative
      of the classroom;
           creating a third window for displaying the
      first selected data stream; and
          creating a fourth window for displaying
      the second selected data stream, wherein
          the third and fourth windows are dis-
      played simultaneously.
   8. A system for conducting distributed learning
   among a plurality of computer systems coupled to
   a network, the system comprising:
       a presenter computer system of the plurality
   of computer systems coupled to the network and
   comprising:
          a content selection control for defining at
      least one remote streaming data source and
      for selecting one of the remote streaming data
      sources for viewing; and
          a presenter streaming data viewer for dis-
      playing data produced by the selected remote
      streaming data source;
       an audience member computer system of the
   plurality of computer systems and coupled to the
   presenter computer system via the network, the
   audience member computer system comprising:
          an audience member streaming data
      viewer for displaying the data produced by the
      selected remote streaming data source; and
6                          WILLIAMSON   v. CITRIX ONLINE, LLC



        a distributed learning server remote from the
    presenter and audience member computer sys-
    tems of the plurality of computer systems and
    coupled to the presenter computer system and the
    audience member computer system via the net-
    work and comprising:
           a streaming data module for providing the
       streaming data from the remote streaming da-
       ta source selected with the content selection
       control to the presenter and audience member
       computer systems; and
           a distributed learning control module for
       receiving communications transmitted be-
       tween the presenter and the audience member
       computer systems and for relaying the com-
       munications to an intended receiving comput-
       er system and for coordinating the operation
       of the streaming data module.
    17. A distributed learning server for controlling a
    presenter computer system and an audience
    member computer system coupled to the distrib-
    uted learning server via a network, the distribut-
    ed learning server comprising:
        a module for providing a first graphical dis-
    play on the presenter computer system, the first
    graphical display comprising:
           a first presenter content selection control
       for selecting a first source of streaming con-
       tent representative of graphical information;
           a first presenter content display region for
       displaying the graphical information repre-
       sented by the streaming content from the first
       selected source;
WILLIAMSON   v. CITRIX ONLINE, LLC                             7



            a second presenter content selection con-
        trol for selecting a second source of streaming
        content representative of graphical infor-
        mation; and
            a second presenter content display region
        for displaying the graphical information rep-
        resented by the streaming content from the
        second selected source, wherein the first and
        second presenter content display regions are
        adapted to display simultaneously; and
            a classroom region for representing the
        audience member computer system coupled to
        the distributed learning server; and
        a module for providing a second graphical dis-
    play on the audience member computer system,
    the second graphical display comprising:
            a first audience member content display
        region for displaying the graphical infor-
        mation represented by the streaming content
        from the first source selected by the content
        selection control; and
            a second audience member content display
        region for displaying the graphical infor-
        mation represented by the streaming content
        from the second source selected by the content
        selection control, wherein the first and second
        audience member content display regions are
        adapted to display simultaneously.
Id. at col. 10 ll. 28–52, col. 11 ll. 26–62, col. 12 ll. 29–
65 (emphases added for relevant terms).
                   II. Procedural History
    Williamson accused Appellees of infringing the ’840
patent based on their alleged manufacture, sale, offer for
sale, use, and importation of various systems and meth-
8                          WILLIAMSON   v. CITRIX ONLINE, LLC



ods of online collaboration. On March 22, 2011, William-
son filed suit in the United States District Court for the
Central District of California specifically asserting in-
fringement of all 24 claims of the ’840 patent. On Sep-
tember 4, 2012, the district court issued a claim
construction order, construing, inter alia, the following
limitations of independent claims 1 and 17: “graphical
display representative of a classroom” and “first graphical
display comprising . . . a classroom region” (collectively,
the “graphical display” limitations). The district court
held that these terms require “a pictorial map illustrating
an at least partially virtual space in which participants
can interact, and that identifies the presenter(s) and the
audience member(s) by their locations on the map.”
    In its claim construction order, the district court also
concluded that the limitation of claim 8, “distributed
learning control module,” was a means-plus-function term
under 35 U.S.C. § 112, para. 6. The district court then
evaluated the specification and concluded that it failed to
disclose the necessary algorithms for performing all of the
claimed functions. The district court thus held claim 8
and its dependent claims 9–16 invalid as indefinite under
§ 112, para. 2.
    Williamson conceded that under the district court’s
claim constructions, none of Appellees’ accused products
infringed independent claims 1 and 17 and their respec-
tive dependent claims 2–7 and 18–24, and that claims 8–
16 were invalid. The parties stipulated to final judgment.
Williamson appeals the stipulated entry of judgment,
challenging these claim construction rulings. We have
jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
                       DISCUSSION
                  I. Standard of Review
    Claim construction is a legal issue that this court re-
views de novo on appeal. Lighting Ballast Control LLC v.
WILLIAMSON   v. CITRIX ONLINE, LLC                         9



Philips Elecs. N. Am. Corp., 744 F.3d 1272, 1276–77 (Fed.
Cir. 2014) (en banc). To ascertain the scope and meaning
of the asserted claims, this court looks to the words of the
claims themselves, the specification, the prosecution
history, and, lastly, any relevant extrinsic evidence.
Phillips v. AWH Corp., 415 F.3d 1303, 1315–17 (Fed. Cir.
2005) (en banc). Whether claim language invokes § 112,
para. 6, 2 is an exercise of claim construction and is there-
fore a question of law, subject to de novo review. Person-
alized Media Commc’ns, LLC v. Int’l Trade Comm’n, 161
F.3d 696, 702 (Fed. Cir. 1998).
          II. The “graphical display” Limitations
    Williamson asserts that the district court erred in its
construction of the graphical display terms by improperly
importing an extraneous “pictorial map” limitation into
the claim. Williamson argues that requiring a “map”
unduly narrows the claims to the preferred embodiment
disclosed in the written description and that there is no
support in the intrinsic record for confining the claims to
a “pictorial map” that identifies the location of the partic-
ipants. Williamson alleges that a proper definition must
require the audience members to be able to interact with
both the presenter and other audience members. He
therefore asserts that the proper construction of the
graphical display terms is “a viewable illustration of an at
least partially virtual space that allows audience mem-
bers to interact with both the presenter and other audi-
ence members.”


    2   Paragraph 6 of 35 U.S.C. § 112 was replaced with
newly designated § 112(f) when § 4(c)(6) of the Leahy–
Smith America Invents Act (“AIA”), Pub. L. No. 112–29,
took effect on September 16, 2012. Because the patent
application that led to the ’840 patent was filed before the
effective date of the AIA, we apply the pre-AIA version of
that section.
10                          WILLIAMSON   v. CITRIX ONLINE, LLC



    Appellees respond that the district court’s construc-
tion correctly limited the claims to a “pictorial map”
consistent with the teachings of the written description.
According to Appellees, this construction does not import
a limitation from the preferred embodiment, but simply
reflects the functional aspects of a “classroom” in a man-
ner that is consistent with what the patentee invented
and disclosed. Moreover, according to Appellees, it is
consistent with the only depiction of a classroom shown in
the ’840 patent, which shows a pictorial map as a seating
chart that identifies the presenters and audience mem-
bers by their locations on the map.
    We agree with Williamson. The district court erred in
construing these terms as requiring a “pictorial map.”
First, the claim language itself contains no such “pictorial
map” limitation. “[I]t is the claims, not the written de-
scription, which define the scope of the patent right.”
Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed.
Cir. 1998); see id. (“[A] court may not import limitations
from the written description into the claims.”). While the
specification discloses examples and embodiments where
the virtual classroom is depicted as a “map” or “seating
chart,” nowhere does the specification limit the graphical
display to those examples and embodiments. This court
has repeatedly “cautioned against limiting the claimed
invention to preferred embodiments or specific examples
in the specification.” Teleflex, Inc. v. Ficosa N. Am. Corp.,
299 F.3d 1313, 1327–28 (Fed. Cir. 2002) (quoting cases).
     Here, there is no suggestion in the intrinsic record
that the applicant intended the claims to have the limited
scope determined by the district court. To the contrary,
the embodiments and examples in the specification of
classroom metaphors relating to “maps” are consistently
described in terms of preference. For example, at column
2, lines 34–39, the specification states that “[t]he class-
room metaphor preferably provides a map of the class-
room showing the relative relationships among the
WILLIAMSON   v. CITRIX ONLINE, LLC                       11



presenters and audience members.” ’840 patent, col. 2 ll.
37–39 (emphasis added). In another example, the graph-
ical display of Figure 6 is described as an “exemplary
display” on the presenter’s computer. Id. at col. 7 ll. 35–
36. That exemplary display includes a window that
“preferably provides a seating chart showing the audience
members and presenters in the classroom or auditorium.”
Id. at col. 9 ll. 5–7 (emphasis added).
    The ’840 patent defines a classroom as “an at least
partially virtual space in which participants can interact.”
Id. at col. 6 ll. 5–7. Nothing further is required, and no
greater definition is mandated by the language of the
claims, the specification, or the prosecution history. As is
well settled, the claims must “not be read restrictively
unless the patentee has demonstrated a clear intention to
limit the claim scope using words or expressions of mani-
fest exclusion or restriction.” Innova/Pure Water, Inc., v.
Safari Water Filtration Sys. Inc., 381 F.3d 1111, 1117
(Fed. Cir. 2004) (internal quotations omitted).
     For the foregoing reasons, we conclude that the dis-
trict court incorrectly construed the graphical display
terms to have a “pictorial map” limitation. We therefore
vacate the stipulated judgment of non-infringement of
claims 1–7 and 17–24. The “graphical display” limitations
in claims 1 and 17 are properly construed as “a graphical
representation of an at least partially virtual space in
which participants can interact.”
      III. The “distributed learning control module”
                        Limitation
   On appeal, Williamson argues that the district court
erred in construing the term “distributed learning control
module” as being governed by 35 U.S.C. § 112, para. 6.
Williamson contends that the district court failed to give
appropriate weight to the “strong” presumption against
means-plus-function claiming that attaches to claim
terms that do not recite the word “means.” Williamson
12                         WILLIAMSON   v. CITRIX ONLINE, LLC



also argues that the district court wrongly focused its
analysis on the word “module” instead of the full term,
ignored the detailed support provided in the written
description, and misapplied our law by failing to view the
term from the perspective of one of ordinary skill in the
art.
    Appellees respond that the district court correctly con-
cluded that the presumption against means-plus-function
claiming was rebutted because “distributed learning
control module” does not have a well understood structur-
al meaning in the computer technology field. Appellees
argue that the “distributed learning control module”
limitation is drafted in the same format as a traditional
means-plus-function limitation, and merely replaces the
term “means” with the “nonce” word “module,” thereby
connoting a generic “black box” for performing the recited
computer-implemented functions. In Appellees’ view,
since the term should be treated as a means-plus-function
claim term and there is no algorithmic structure for
implementing the claimed functions in the written de-
scription, the finding of indefiniteness should be affirmed.
    We agree with Williamson that the district court
erred in concluding that “distributed learning control
module” is a means-plus-function claim term.
    Section 112, para. 6, provides that “[a]n element in a
claim for a combination may be expressed as a means or
step for performing a specified function without the
recital of structure, material, or acts in support thereof.”
35 U.S.C. § 112, para. 6 (1994). In Personalized Media
Commc’ns, LLC v. International Trade Commission, 161
F.3d 696 (Fed. Cir. 1998), and again in DePuy Spine, Inc.
v. Medtronic Sofamor Danek, Inc., 469 F.3d 1005 (Fed.
Cir. 2006), we stated that the failure to use the word
“means” in a claim limitation created a rebuttable pre-
sumption that 35 U.S.C. § 112, para. 6 did not apply. See
Personalized Media, 161 F.3d at 703–04; DePuy Spine,
WILLIAMSON   v. CITRIX ONLINE, LLC                         13



469 F.3d at 1023. This presumption is “a strong one that
is not readily overcome.” Lighting World, Inc. v. Birch-
wood Lighting, Inc., 382 F.3d 1354, 1358 (Fed. Cir. 2004).
To rebut this strong presumption, it must be demonstrat-
ed that “skilled artisans, after reading the patent, would
conclude that [the] claim limitation is so devoid of struc-
ture that the drafter constructively engaged in means-
plus-function claiming.” Inventio AG v. ThyssenKrupp
Elevator Ams. Corp., 649 F.3d 1350, 1357 (Fed. Cir. 2011).
A claimed expression cannot be said to be devoid of struc-
ture if it is used “in common parlance or by persons of
skill in the pertinent art to designate structure, even if
the term covers a broad class of structures and even if the
term identifies the structures by their function.” Lighting
World, 382 F.3d at 1359–60.
    “Technical dictionaries, which are evidence of the un-
derstandings of persons of skill in the technical arts” may
inform whether claim terms connote structure. Linear
Tech. Corp. v. Impala Linear Corp., 379 F.3d 1311, 1320
(Fed. Cir. 2004); Mass. Inst. of Tech. v. Abacus Software,
462 F.3d 1344, 1355 (Fed. Cir. 2006). Moreover, in cir-
cumstances in which “[a] structure-connoting term . . . is
coupled with a description of [its] operation, sufficient
structural meaning generally will be conveyed to persons
of ordinary skill in the art.” Linear Tech, 379 F.3d at
1320. In making this assessment, it is important to
consider the claimed expression as a whole, and not
merely any single word, as well as its surrounding textual
context. See Apex Inc. v. Raritan Computer, Inc., 325 F.3d
1364, 1372 (Fed. Cir. 2003) (“[T]he primary source of this
error lies in the district court’s reliance on single words of
the limitations . . . as opposed to the limitations as a
whole . . . .”); Mass. Inst. of Tech., 462 F.3d at 1356 (“The
claim language here too does not merely describe a circuit;
it adds further structure by describing the operation of
the circuit.”).
14                        WILLIAMSON   v. CITRIX ONLINE, LLC



    The district court here failed to give weight to the
strong presumption that 35 U.S.C. § 112, para. 6, did not
apply based on the absence of the word “means.” “[W]e
have seldom held that a limitation not using the term
‘means’ must be considered to be in means-plus-function
form,” and “the circumstances must be [unusual] to over-
come the presumption.” Lighting World, 382 F.3d at 1362.
    Moreover, in determining that the strong presumption
was overcome, the district court erred: (1) in failing to
appreciate that the word “module” has a number of dic-
tionary meanings with structural connotations; (2) in
placing undue emphasis on the word “module” separate
and apart from the claimed expression “distributed learn-
ing control module”; and (3) in failing to give proper
weight to the surrounding context of the rest of the claim
language and the supporting text of the specification in
reaching the conclusion that the drafter employed means-
plus-function claiming.
    The district court, in characterizing the word “mod-
ule” as a mere nonce word, failed to appreciate that the
word “module” has understood dictionary meanings as
connoting either hardware or software structure to those
skilled in the computer arts. While the parties here have
not cited any dictionaries, we have frequently looked to
the dictionary to determine if a disputed term has
achieved recognition as a term denoting structure.
“[J]udges are free to consult dictionaries and technical
treatises ‘at any time in order to better understand the
underlying technology and may also rely on dictionary
definitions when construing claim terms, so long as the
dictionary definition does not contradict any definition
found in or ascertained by a reading of the patent docu-
ments.’” Phillips, 415 F.3d at 1322–23 (quoting Vitronics
Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1584 n.6 (Fed.
Cir. 1996)); see also Lighting World, 382 F.3d at 1360;
Mass. Inst. of Tech., 462 F.3d at 1355. The IBM Corpora-
tion, IBM Dictionary of Computing 439 (1st ed. 1994)
WILLIAMSON   v. CITRIX ONLINE, LLC                     15



defines “module” as a “packaged functional hardware unit
designed for use with other components” and a “part of a
program that usually performs a particular function of
related functions.” See also Alan Freedman, The Comput-
er Glossary 268 (8th ed. 1998) (defining “module” as a
“self-contained hardware or software component that
interfaces with a larger system”); John Daintith & Ed-
mund Wright, Dictionary of Computing 315 (4th ed. 1996)
(defining “module” as a “programming or specification
construct that defines a software component” and a “com-
ponent of a hardware system that can be subdivided”).
These definitions all show that the term “module” has a
structure connoting meaning to persons of ordinary skill
in the computer arts.
    Appellees cite an unpublished opinion in Ranpak
Corp. v. Storopack, Inc., No. 98-1009, available at 1998
WL 513598 (Fed. Cir. July 15, 1998), to support their
conclusion that “module” means nothing more than
“means.” That case, however, dealt with reconciling two
claimed expressions that differed only in those words.
The court made no reference to any dictionary meanings
of the word “module” and made no analysis or ruling as to
the meaning of the word “module” beyond the limited
context of the issue confronting it in that case.
    Not only did the district court fail to appreciate the
structure-connoting meanings of the word “module”
reflected in dictionaries, it also failed to consider the
claimed expression “distributed learning control module”
as a whole. This was error. See Apex, 325 F.3d at 1372.
The adjectival modifiers “distributed learning control”
cannot be ignored and serve to further narrow the scope of
the expression as a whole. Id. at 1374. Here, the “dis-
tributed learning control module” is claimed as a part of
the definite structure “distributed learning server” and
“receive[s] communications transmitted between the
presenter and the audience member computer systems,”
“relay[s] the communications to an intended receiving
16                          WILLIAMSON   v. CITRIX ONLINE, LLC



computing system,” and “coordinat[es] the operation of
the streaming data module.” ’840 patent, col. 11 ll. 55–62.
These claimed interconnections and intercommunications
support the conclusion that one of ordinary skill in the art
would understand the expression “distributed learning
control module” to connote structure.
    The specification further explains that the distributed
learning control module operates as a functional unit of
the distributed learning server and coordinates the opera-
tion of the streaming data module through input from the
presenter computer system. Id. at col. 5 ll. 34–36. The
specification also makes clear that the distributed learn-
ing control module includes software that runs on a
portion of the distributed learning server. Id. at col. 5 ll.
40–58. While the supporting specification describes the
claimed expression “distributed learning control module”
in a high degree of generality, in some respects using
functional expressions, it is difficult to conclude that it is
devoid of structure. See Lighting World, 382 F.3d at
1359–60 (A claimed expression cannot be said to be devoid
of structure if it is used “in common parlance or by per-
sons of skill in the pertinent art to designate structure,
even if the term covers a broad class of structures and
even if the term identifies the structures by their func-
tion.”)
    For these reasons, we determine that the Appellees
have failed to overcome the strong presumption that the
expression “distributed learning control module” is not
subject to 35 U.S.C. § 112, para. 6. We therefore vacate
the district court’s determination that claims 8–12 are
invalid under 35 U.S.C. § 112, para. 2, based on that
construction.
                        CONCLUSION
    Because the district court erred in construing the
“graphical display” limitations of claims 1 and 17 and the
“distributed learning control module” limitation of claim
WILLIAMSON   v. CITRIX ONLINE, LLC                   17



8, we vacate the stipulated judgment of non-infringement
of claims 1–7 and 17–24 and of invalidity of claims 8–16
and remand the case to the district court.
              VACATED AND REMANDED
                            COSTS
   Costs to Williamson.
  United States Court of Appeals
      for the Federal Circuit
                 ______________________

 RICHARD A. WILLIAMSON, Trustee for At Home
       Bondholders Liquidating Trust,
              Plaintiff-Appellant,

                            v.

  CITRIX ONLINE, LLC, CITRIX SYSTEMS, INC.,
    MICROSOFT CORPORATION, AND ADOBE
              SYSTEMS, INC.,
             Defendants-Appellees,

                          AND

WEBEX COMMUNICATIONS, INC., CISCO WEBEX,
       LLC, AND CISCO SYSTEMS, INC.,
             Defendants-Appellees,

                          AND

     INTERNATIONAL BUSINESS MACHINES
              CORPORATION,
              Defendant-Appellee.
            ______________________

                       2013-1130
                 ______________________

   Appeal from the United States District Court for the
Central District of California in No. 11-CV-2409, Judge A.
Howard Matz.
                  ______________________
2                          WILLIAMSON   v. CITRIX ONLINE, LLC



REYNA, Circuit Judge, dissenting.
    I agree with the majority that the district court erred
in finding that the “graphical display representative of a
classroom” terms require a pictorial map. The majority,
however, ignores critical evidence showing that an image
of a visually depicted virtual classroom is required.
Further, I do not agree that claim 8 of the ’840 patent
discloses sufficient structure to keep the claim limitation
“distributed learning control module” outside of the
requirements of 35 U.S.C. § 112, paragraph 6. For these
and the reasons set forth below, I respectfully dissent.
                             I
    The majority reverses the district court’s conclusion
that the “graphical display representative of a classroom”
terms require a pictorial map and construes the terms as
“a graphical representation of an at least partially virtual
space in which participants can interact.” While the
majority is correct that the claims of the ’840 patent do
not require a pictorial map, the majority has adopted a
construction that ignores a critical limitation. As re-
viewed below, the specification and prosecution history
make clear that the “graphical display representative of a
classroom” terms are properly construed as requiring a
visually depicted virtual classroom.
    During patent prosecution, the applicant explained
that the invention is distinct from the prior art because
the patent requires a “visual virtual classroom” displayed
on both a first and second computer system:
    Additionally, [the prior art] does not disclose the
    claimed feature of “creating a graphical display
    representative of the classroom” on a second com-
    puter system coupled to the network. The present
    invention allows both a first computer system (for
    example, the presenter computer system) and a
    second computer system (for example, an audience
WILLIAMSON   v. CITRIX ONLINE, LLC                       3



   member) to view a graphical display of the class-
   room. This claimed feature of the present inven-
   tion allows the audience members to interact in a
   visual virtual classroom environment with both
   the presenter and other audience members.
   By contrast, [the prior art] merely discloses “[as]
   the students log in, their seating locations in the
   classroom are shown by a highlighted icon in the
   classroom map on the teacher’s screen.” . . . [The
   prior art] does not teach or suggest displaying a
   graphical display representative of a classroom on
   a student’s screen.
J.A. 1267-68 (original emphasis removed and emphases
added). These statements in conjunction with the pa-
tent’s claim terms confirm the significance of displaying a
visually depicted virtual classroom.
    The “classroom metaphor” is used extensively in
characterizing the operation, and touting the benefits, of
the inventions embodied in the ’840 patent. The Abstract
teaches that “[t]he classroom environment module pro-
vides a classroom metaphor having a podium and rows of
seats to the presenter and audience computer systems.”
’840 patent Abstract. The Summary of the Invention
states that the drawbacks of the prior art are overcome
“by a distributed learning system that uses industry-
standard computer hardware and software linked by a
network like the Internet to provide a classroom- or
auditorium-like metaphor to at least one presenter and at
least one audience member.” Id. col. 2 ll. 10-14. The
patent further teaches that a “feedback region” on the
presenter’s computer “preferably displays a graphical
representation of the classroom” and the “classroom
environment module” is used to provide “a classroom- or
auditorium-like metaphor to the presenter and audience
members.” Id. col. 3 ll. 11-13, col. 5 l. 67-col. 6 l. 1.
4                          WILLIAMSON   v. CITRIX ONLINE, LLC



    In this case, the repeated mention of the classroom
metaphor within the context of the invention and the
importance of a visually depicted virtual classroom in the
prosecution history indicate that the “graphical display
representative of a classroom” terms require a visually
depicted virtual classroom. The construction derived by
the majority reads out this important limitation that
distinguishes the invention from the prior art. See Callic-
rate v. Wadsworth Mfg., Inc., 427 F.3d 1361, 1369 (Fed.
Cir. 2005) (holding that it was error for the district court
to read out a limitation clearly required by the claim
language and specification). It is error to read a claim too
broadly, as it is to read a claim too narrowly. See, e.g.,
Phillips v. AWH Corp., 415 F.3d 1303, 1321 (Fed. Cir.
2005) (en banc). In reading out this important limitation
on the “graphical display representative of a classroom”
terms, the majority sidesteps our well established rules of
claim construction, causing them to reach an erroneous
result.
                             II
    The majority also concludes that the district court
erred in construing the term “distributed learning control
module” as a means-plus-function term. The majority
holds that the term “distributed learning control module”
connotes sufficient structure to keep the term outside the
scope of 35 U.S.C. § 112, paragraph 6. Maj. Op. at 16.
The majority, however, finds structure where none exists.
    Here, “distributed learning control module” does not
connote sufficiently definite structure, and thus, the term
is governed by § 112, paragraph 6. In place of using the
term “means,” this claim limitation uses “module.” The
claim limitation then recites three functions performed by
the “distributed learning control module”:
    [D]istributed learning control module for [(1)] re-
    ceiving communications transmitted between the
    presenter and the audience member computer
WILLIAMSON   v. CITRIX ONLINE, LLC                          5



    systems and [(2)] for relaying the communications
    to an intended receiving computer system and
    [(3)] for coordinating the operation of the stream-
    ing data module.”
’840 patent col. 11 ll. 56-61. This claim limitation is in the
traditional means-plus-function format, with the minor
substitution of the term “module” for “means.” The claim
language explains what the functions are, but does not
disclose how the functions are performed. 1 In this case,
the term “module” is a “nonce” word, a generic word
inherently devoid of structure.
    “Module” is a “nonce” word that can operate as a sub-
stitute for “means” in the context of § 112, paragraph 6.
As the district court found, “‘module’ is simply a generic
description for software or hardware that performs a
specified function.” 2 J.A. 31. Generic terms such as
“mechanism,” “element,” “device,” and other “nonce”
words that reflect nothing more than verbal constructs
may be used in a claim in a manner that is tantamount to
using the word “means” because they “typically do not
connote sufficiently definite structure” and therefore may
invoke § 112, paragraph 6. Mass. Inst. of Tech. v. Abacus
Software, 462 F.3d 1344, 1354 (Fed. Cir. 2006); see gener-
ally M.P.E.P. § 2181 (“The following is a list of non-
structural     generic     placeholders    that  may       in-
voke . . . 35 U.S.C. [§] 112, paragraph 6: ‘mechanism for,’
‘module for,’ ‘device for,’ ‘unit for,’ ‘component for,’ ‘ele-



    1   As we have often held, structure may also be pro-
vided by describing the claim limitation’s operation, such
as its input, output, or connections.       Apple Inc. v.
Motorola, Inc., 757 F.3d 1286, 1299 (Fed. Cir. 2014).
    2   Williamson concedes this point. Appellant’s Op.
Br. at 43 (“[T]he term ‘module,’ standing alone, is capable
of operating as a ‘nonce word.’”).
6                          WILLIAMSON   v. CITRIX ONLINE, LLC



ment for,’ ‘member for,’ ‘apparatus for,’ ‘machine for,’ or
‘system for.’”) (emphasis added).
     Recognizing that the term “module” is a mere place-
holder word with no definition in the specification, the
majority resorts to extrinsic evidence in the form of the
following dictionary definitions of the term “module”:
      •   The IBM Corporation, IBM Dictionary of Com-
          puting 439 (1st ed. 1994) - a packaged functional
          hardware unit designed for use with other com-
          ponents and a part of a program that usually
          performs a particular function of related func-
          tions.
      •   Alan Freedman, The Computer Glossary 268
          (8th ed. 1998) - a self-contained hardware or
          software component that interfaces with a larg-
          er system.
      •   John Daintith & Edmund Wright, Dictionary of
          Computing 315 (4th ed. 1996) - programming or
          specification construct that defines a software
          component and a component of a hardware sys-
          tem that can be subdivided.
Maj. Op. at 14-15. The majority concludes that “[t]hese
definitions all show that the term ‘module’ has a structure
connoting meaning to persons of ordinary skill in the
computer arts.” Id. at 15.
    The definitions, however, only identify that “module”
is either hardware, software, or both. Without more, the
concept of generic software or hardware only reflects
function. It refers only to a “general category of whatever
may perform specified functions.” Robert Bosch, LLC v.
Snap-On Inc., --- F.3d ---, No. 2014-1040, 2014 WL
5137569, at *4 (Fed. Cir. Oct. 14, 2014) (holding that the
claim terms “program recognition device” and “program
loading device” are governed by 35 U.S.C. § 112, para-
graph 6 because they fail to connote sufficient structure).
WILLIAMSON   v. CITRIX ONLINE, LLC                          7



Consider that the IBM Dictionary of Computing uses the
terms “functional hardware unit” and “[something] that
performs a particular function.” Maj. Op. at 14-15. The
Computer Glossary similarly defines “module” in terms of
its function: “interfac[ing].” Id. at 15. Finally, the Dic-
tionary of Computing defines “module” as a “construct” or
“component.” Id. The definitions disclose what software
or hardware potentially do, not how it is done.
     Numerous other dictionary definitions from the rele-
vant time period also define the “module” in functional
terms. For example, the Webster’s New World Dictionary
of Computer Terms 331 (6th ed. 1997) defines “module” as
“[i]n a program, a unit or section that can function on its
own.” The IEEE Standard Dictionary of Electrical and
Electronics Terms 817 (5th ed. 1993) defines “module” as
“a logically separable part of a program” and goes on to
note that “[t]he terms ‘module,’ ‘component,’ and ‘unit’ are
often used interchangeably.” 3 The American Heritage
College Dictionary 877 (3d ed. 1997) defines “module” as
“[a] portion of a program that carries out a specific func-
tion and may be used alone or combined with other mod-
ules of the same program.” These definitions, again,
generally define “module” as generic software or hardware
that performs a certain function.
    The majority also undertakes a grammatical approach
noting that the “adjectival modifiers . . . cannot be ignored
and serve to further narrow the scope of the expression as
a whole.” Maj. Op. at 15. The majority points to the
terms “distributed,” “learning,” and “control” as modifiers


    3    Cf. M.P.E.P. § 2181 (“The following is a list of non-
structural     generic    placeholders     that   may      in-
voke . . . 35 U.S.C. [§] 112, paragraph 6: ‘mechanism for,’
‘module for,’ ‘device for,’ ‘unit for,’ ‘component for,’ ‘ele-
ment for,’ ‘member for,’ ‘apparatus for,’ ‘machine for,’ or
‘system for.’”) (emphases added).
8                          WILLIAMSON   v. CITRIX ONLINE, LLC



that connote structure. Id. at 15. While the majority is
correct that the presence of modifiers can change the
meaning of a claimed nonce word, the modifiers relied on
by the majority do not provide any structural significance
to the term “module.” The ordinary meanings of these
terms do not connote structure, and neither the specifica-
tion nor the prosecution history gives these adjectives any
structural significance in this claim.
    Finally, the majority concedes that the “distributed
learning control module” operates as a functional unit
that is “described in a high degree of generality” in the
specification using “functional expressions.” Id. at 16. In
my view, a “functional unit” claimed at a “high degree of
generality” is pure functional claiming. The term “dis-
tributed learning control module” fails to connote any
structure, the presumption against the application of
means-plus-function claiming is rebutted, and, therefore,
§ 112, paragraph 6 applies.
                            III
    Although the majority does not reach the issue of cor-
responding structure, I believe this analysis is necessary
because the claim limitation at issue fails to disclose
sufficient structure to keep “distributed learning control
module” outside of the requirements of § 112, para-
graph 6. Thus, I turn to the issue of whether the specifi-
cation discloses sufficient structure that corresponds to
the claimed function. I conclude that it does not.
    The district court identified three claimed functions
associated with the “distributed learning control module”
term: (1) receiving communications transmitted between
the presenter and the audience member computer sys-
tems; (2) relaying the communications to an intended
receiving computer system; and (3) coordinating the
operation of the streaming data module. The district
court concluded that the specification fails to disclose
structure corresponding to the “coordinating” function.
WILLIAMSON   v. CITRIX ONLINE, LLC                        9



    On appeal, it is undisputed that the claimed “coordi-
nating” function is associated with the “distributed learn-
ing control module.” Where there are multiple claimed
functions, as we have here, the patentee must disclose
adequate corresponding structure to perform all of the
claimed functions.      Noah Sys., Inc. v. Intuit Inc.,
675 F.3d 1302, 1318-19 (Fed. Cir. 2012).
    The district court was correct that the specification of
the ’840 patent fails to disclose corresponding structure
because the specification does not set forth an algorithm
for performing the claimed functions. See Aristocrat
Techs. Austl. Pty Ltd. v. Int’l Game Tech., 521 F.3d 1328,
1333 (Fed. Cir. 2008). Thus, I would affirm the judgment
that claims 8-16 are invalid for indefiniteness under
35 U.S.C. § 112, paragraph 2.
   For the foregoing reasons, I dissent.
