The Collaborative International Dictionary of English v.0.48:

Sketch \Sketch\, v. t. [imp. & p. p. Sketched; p. pr. & vb. n.
   Sketching.] [Cf D. schetsen, It. schizzare. See Sketch,
   n.]
   1. To draw the outline or chief features of; to make a rought
      of.
      [1913 Webster]

   2. To plan or describe by giving the principal points or
      ideas of.
      [1913 Webster]

   Syn: To delineate; design; draught; depict.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sketch \Sketch\, n. [D. schets, fr. It. schizzo a sketch, a
   splash (whence also F. esquisse; cf. Esquisse.); cf. It.
   schizzare to splash, to sketch.]
   An outline or general delineation of anything; a first rough
   or incomplete draught or plan of any design; especially, in
   the fine arts, such a representation of an object or scene as
   serves the artist's purpose by recording its chief features;
   also, a preliminary study for an original work.
   [1913 Webster]

   Syn: Outline; delineation; draught; plan; design.

   Usage: Sketch, Outline, Delineation. An outline gives
          only the bounding lines of some scene or picture. A
          sketch fills up the outline in part, giving broad
          touches, by which an imperfect idea may be conveyed. A
          delineation goes further, carrying out the more
          striking features of the picture, and going so much
          into detail as to furnish a clear conception of the
          whole. Figuratively, we may speak of the outlines of a
          plan, of a work, of a project, etc., which serve as a
          basis on which the subordinate parts are formed, or of
          sketches of countries, characters, manners, etc.,
          which give us a general idea of the things described.
          --Crabb.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sketch \Sketch\, v. i.
   To make sketches, as of landscapes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sketch
    n 1: preliminary drawing for later elaboration; "he made several
         studies before starting to paint" [syn: sketch, study]
    2: a brief literary description [syn: sketch, vignette]
    3: short descriptive summary (of events) [syn: sketch,
       survey, resume]
    4: a humorous or satirical drawing published in a newspaper or
       magazine [syn: cartoon, sketch]
    v 1: make a sketch of; "sketch the building" [syn: sketch,
         chalk out]
    2: describe roughly or briefly or give the main points or
       summary of; "sketch the outline of the book"; "outline his
       ideas" [syn: sketch, outline, adumbrate]

Moby Thesaurus II by Grady Ward, 1.0:

329 Moby Thesaurus words for "sketch":
   Grand Guignol, Passion play, Tom show, abbreviation, abbreviature,
   abrege, abridge, abridgment, abstract, act, act as foil, adumbrate,
   afterpiece, antimasque, appear, article, audience success, ballet,
   barnstorm, bit, black and white, block in, block out, blueprint,
   bomb, brief, bring to life, broadcast drama, brouillon,
   burlesque show, cameo, capsule, capsulize, cartoon, catalog,
   cataloging, causerie, chalk, chalk out, character,
   character sketch, characterization, characterize, charade,
   charcoal, charcoal drawing, chart, chaser, chiaroscuro,
   cliff hanger, closet drama, color, come out, comedy drama, compend,
   condensation, condense, condensed version, conspectus, copy,
   crayon, critical success, crosshatch, curtain, curtain call,
   curtain raiser, dash off, daub, daytime serial, delineate,
   delineation, depict, depiction, descant, describe, description,
   design, detail, details, develop, diagram, dialogue, digest,
   discourse, discussion, disquisition, dissertation, divertimento,
   divertissement, documentary drama, doodle, draft, drama,
   dramalogue, dramatic play, dramatic series, draw, drawing,
   duodrama, duologue, ebauche, elevation, emote, emotionalize,
   epic theater, epilogue, epitome, esquisse, essay, etude, evocation,
   evoke, examination, excursus, exode, exodus, experimental theater,
   exposition, expository scene, express, extravaganza, failure,
   feature, figure, finale, first approach, flop, gasser,
   get top billing, give words to, giveaway, graph, graphic account,
   ground plan, happening, hatch, head, hit, hit show, hoke act,
   homily, house plan, ichnography, image, imagery, impression,
   improvisational drama, interlude, intermezzo, intermission,
   introduction, introductory study, itemization, lay, lay off,
   lay out, legitimate drama, limn, limning, line, line drawing,
   lucubration, map, map out, mark off, mark out, masque, melodrama,
   memoir, mime, minstrel show, miracle, miracle play, monodrama,
   monograph, monologue, morality, morality play, morceau,
   music drama, musical revue, mystery, mystery play, note, number,
   nutshell, opera, outline, overview, pageant, paint,
   paint a picture, pandect, panel show, pantomime, paper, paragraph,
   particularization, pastel, pastoral, pastoral drama, patter,
   pattern, pen-and-ink, pencil, pencil drawing, perform, photograph,
   picture, picturize, piece, play, play the lead, playact, playlet,
   plot, plot out, portrait, portraiture, portray, portrayal, precis,
   preliminary study, problem play, profile, projection, prolegomenon,
   prologue, psychodrama, quiz show, radio drama, register, render,
   rendering, rendition, represent, representation, research paper,
   review, revue, rough, rough copy, rough draft, rough in, rough out,
   rough outline, routine, rubric, scene, scratch, screed, scumble,
   sensational play, serial, set forth, set out, shade, shorten,
   shortened version, show, shtick, silhouette, silver-print drawing,
   sinopia, sitcom, situation comedy, skeleton, sketch out, skit,
   soap, soap opera, sociodrama, song and dance, special article,
   specification, spectacle, stage play, stage show,
   stand-up comedy act, star, steal the show, stencil, stooge,
   straight drama, striptease, study, success, summarize, survey,
   suspense drama, syllabus, synopsis, synopsize, table, tableau,
   tableau vivant, talk show, teleplay, television drama,
   television play, term paper, theater of cruelty, theme, thesis,
   thumbnail sketch, tint, topical outline, total theater, trace,
   tracing, tract, tractate, tread the boards, treatise, treatment,
   troupe, turn, upstage, variety show, vaudeville, vaudeville show,
   vehicle, vignette, vivid description, word painting,
   word-of-mouth success, work, working drawing, write