Outline, 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. Painters, by their outlines, colors, lights, and shadows, represent the same in their pictures. Dryden.
2. Fig.: A sketch of any scheme; a preliminary or general indication of a plan, system, course of thought, etc.; as, the outline of a speech. But that larger grief . . . Is given in outline and no more. Tennyson.
Syn. -- Sketch; draught; delineation. See Sketch.
1 other Webster entry under this spelling
Outline, v. t. [imp. & p. p. Outlined; p. pr. & vb. n. Outlining.]
1. To draw the outline of.
2. Fig.: To sketch out or indicate as by an outline; as, to outline an argument or a campaign.
Shades of meaning
Fernald has no entry of its own for outline; he lists it under abridgment, sketch.
Where he writes about it:
An outline or synopsis is a kind of sketch closely following the plan. — from abridgment
An outline gives only the bounding or determining lines of a figure or a scene; a sketch may give not only lines, but shading and color, but is hasty and incomplete. — from sketch
The lines of a sketch are seldom so full and continuous as those of an outline, being, like the shading or color, little more than indications or suggestions according to which a finished picture may be made; the artist's first representation of a sunset, the hues of which change so rapidly, must of necessity be a sketch. — from sketch
Draft and plan apply especially to mechanical drawing, of which outline, sketch, and drawing are also used; a plan is strictly a view from above, as of a building or machine, giving the lines of a horizontal section, originally at the level of the ground, now in a wider sense at any height; as, a plan of the cellar; a plan of the attic. — from sketch
In written composition an outline gives simply the main divisions, and in the case of a sermon is often called a skeleton; a somewhat fuller suggestion of illustration, treatment, and style is given in a sketch. — from sketch