The Collaborative International Dictionary of English v.0.48:

icon \i"con\ ([imac]"k[o^]n), n. [Also spelled ikon.] [L., fr.
   Gr. e'ikw`n.]
   1. An image or representation; a portrait or pretended
      portrait.
      [1913 Webster]

            Netherlands whose names and icons are published.
                                                  --Hakewill.
      [1913 Webster]

   2. (Gr. Ch.) A sacred picture representing the Virgin Mary,
      Christ, a saint, or a martyr, and having the same function
      as an image of such a person in the Latin Church. The term
      is used especially for a highly stylized and
      conventionalized representation of a holy person, rich in
      symbolism and used in devotional services in many of the
      eastern Orthodox churches, especially the Greek and
      Russian Orthodox Churches.
      [Webster 1913 Suppl. +PJC]

   3. a symbol, especially a symbol whose form suggests its
      meaning or the object it represents.
      [PJC]

   4. (Computers) a graphical symbol for a data object whose
      form suggests the nature or function of the object;
      especially, such a symbol as viewed on the computer
      screen.

   Note: In a graphical user interface, pointing to and clicking
         on an icon may cause any of several types of actions,
         such as opening a file or executing a program,
         depending on how the icon properties are defined.
         [PJC]

   5. any object of uncritical devotion.
      [PJC]

            The former congresswoman and Vice-Presidential
            candidate Geraldine Ferraro is still an icon to many
            party members.                        --The New York
                                                  Times, April
                                                  16, 1998
      [PJC]

   6. an outstanding example of something which has come to
      represent the class of things to which it belongs; a
      paragon; used of persons as well as objects.
      [PJC]

WordNet (r) 3.0 (2006):

icon
    n 1: (computer science) a graphic symbol (usually a simple
         picture) that denotes a program or a command or a data file
         or a concept in a graphical user interface
    2: a visual representation (of an object or scene or person or
       abstraction) produced on a surface; "they showed us the
       pictures of their wedding"; "a movie is a series of images
       projected so rapidly that the eye integrates them" [syn:
       picture, image, icon, ikon]
    3: a conventional religious painting in oil on a small wooden
       panel; venerated in the Eastern Church [syn: icon, ikon]

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "icon":
   Agnus Dei, Holy Grail, Host, Pieta, Sanctus bell, Sangraal,
   abstract, abstraction, altarpiece, ark, asperger, asperges,
   aspergillum, bambino, beadroll, beads, block print, candle, censer,
   certified copy, chaplet, ciborium, collage, color print, companion,
   copy, counterfeit, cross, crucifix, cruet, cyclorama, daub,
   dead ringer, diptych, double, duplicate, ectype, effigy, engraving,
   eucharistial, exact likeness, fair copy, faithful copy, fake,
   fellow, forgery, fresco, glosseme, holy cross, holy water,
   holy-water sprinkler, idol, illumination, illustration, image,
   imitation, incensory, lexeme, lexical form, likeness, living image,
   living picture, match, mate, matzo, menorah, mezuzah, mikvah,
   miniature, mirroring, model, monstrance, montage, morpheme, mosaic,
   mural, osculatory, ostensorium, panorama, paschal candle,
   pasticcio, pastiche, pax, phony, photograph, phrase, phylacteries,
   picture, portrait, prayer shawl, prayer wheel, print, pyx,
   reflection, relics, representation, reproduction, resemblance,
   rood, rosary, rubbing, sacramental, sacred relics, sacring bell,
   semasiological unit, semblance, sememe, shadow, shofar, sign,
   signifiant, significant, similitude, simulacrum, spit and image,
   spitting image, stained glass window, stencil, still life, sukkah,
   symbol, tabernacle, tableau, tallith, tapestry, term, thurible,
   token, trace, tracing, triptych, twin, type, urceole, veronica,
   very image, very picture, vigil light, votive candle,
   wall painting, word



The Free On-line Dictionary of Computing (30 December 2018):

Icon

    A descendant of SNOBOL4 with Pascal-like
   syntax, produced by Griswold in the 1970's.  Icon is a
   general-purpose language with special features for string
   scanning.  It has dynamic types: records, sets, lists,
   strings, tables.  If has some object oriented features but
   no modules or exceptions.  It has a primitive Unix
   interface.

   The central theme of Icon is the generator: when an expression
   is evaluated it may be suspended and later resumed, producing
   a result sequence of values until it fails.  Resumption takes
   place implicitly in two contexts: iteration which is
   syntactically loop-like ('every-do'), and goal-directed
   evaluation in which a conditional expression automatically
   attempts to produce at least one result.  Expressions that
   fail are used in lieu of Booleans.  Data backtracking is
   supported by a reversible assignment.  Icon also has
   co-expressions, which can be explicitly resumed at any time.

   Version 8.8 by Ralph Griswold  includes
   an interpreter, a compiler (for some platforms) and a
   library (v8.8).  Icon has been ported to Amiga, Atari,
   CMS, Macintosh, Macintosh/MPW, MS-DOS, MVS, OS/2,
   Unix, VMS, Acorn.

   See also Ibpag2.

   (ftp://cs.arizona.edu/icon/), MS-DOS FTP
   (ftp://bellcore.com norman/iconexe.zip).

   Usenet newsgroup: news:comp.lang.icon.

   E-mail: , .

   Mailing list: icon-group@arizona.edu.

   ["The Icon Programmming Language", Ralph E. Griswold and Madge
   T. Griswold, Prentice Hall, seond edition, 1990].

   ["The Implementation of the Icon Programmming Language", Ralph
   E. Griswold and Madge T. Griswold, Princeton University Press
   1986].

   (1992-08-21)


The Free On-line Dictionary of Computing (30 December 2018):

icon

    A small picture intended to represent something (a
   file, directory, or action) in a graphical user interface.
   When an icon is clicked on, some action is performed such as
   opening a directory or aborting a file transfer.

   Icons are usually stored as bitmap images.  Microsoft
   Windows uses a special bitmap format with file name extension
   ".ico" as well as embedding icons in executable (".exe") and
   Dynamically Linked Library (DLL) files.

   The term originates from Alan Kay's theory for designing
   interfaces which was primarily based on the work of Jerome
   Bruner.  Bruner's second developmental stage, iconic, uses a
   system of representation that depends on visual or other
   sensory organization and upon the use of summarising images.

   IEEE publication

(http://ieee.org/organizations/history_center/cht_papers/Barnes.pdf).

   [What MS tool can create .ico files?]

   (2003-08-01)