The Collaborative International Dictionary of English v.0.48:

Outline \Out"line`\, v. t. [imp. & p. p. Outlined; p. pr. &
   vb. n. Outlining.]
   1. To draw the outline of.
      [1913 Webster]

   2. Fig.: To sketch out or indicate as by an outline; to
      create a general framework of (a plan, system, discourse,
      course of thought), for which the details need to be
      added; as, to outline an argument or a campaign.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Outline \Out"line`\, n.
   1.
      (a) The line which marks the outer limits of an object or
          figure; the exterior line or edge; contour.
      (b) In art: A line drawn by pencil, pen, graver, or the
          like, by which the boundary of a figure is indicated.
      (c) A sketch composed of such lines; the delineation of a
          figure without shading.
          [1913 Webster]

                Painters, by their outlines, colors, lights, and
                shadows, represent the same in their pictures.
                                                  --Dryden.
          [1913 Webster]

   2. Fig.: A sketch of any scheme; a preliminary or general
      indication of a plan, system, discourse, course of
      thought, etc.; as, the outline of a speech.
      [1913 Webster]

            But that larger grief . . .
            Is given in outline and no more.      --Tennyson.
      [1913 Webster]

   Syn: Sketch; draught; delineation. See Sketch.
        [1913 Webster]

WordNet (r) 3.0 (2006):

outline
    n 1: the line that appears to bound an object [syn: outline,
         lineation]
    2: a sketchy summary of the main points of an argument or theory
       [syn: outline, synopsis, abstract, precis]
    3: a schematic or preliminary plan [syn: outline, schema,
       scheme]
    v 1: 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]
    2: draw up an outline or sketch for something; "draft a speech"
       [syn: draft, outline]
    3: trace the shape of [syn: delineate, limn, outline]