[out.line] n (1662) 1 a: a line that marks the outer limits of an object or figure: boundary b: shape
2. a: a style of drawing in which contours are marked without shading b: a sketch in outline 3 a: a condensed treatment of a particular subject "an ~ of world history" b: a summary of a written work: synopsis
4: a preliminary account of a project: plan
5: a fishing line set out overnight: trotline syn outline, contour, profile, silhouette mean the line that bounds and gives form to something. outline applies to a line marking the outer limits or edges of a body or mass "traced the outline of his hand". contour stresses the quality of an outline or a bounding surface as being smooth, jagged, curving, or sharply angled "a car with flowing contours". profile suggests a varied and sharply defined outline against a lighter background "a portrait of her face in profile". silhouette suggests a shape esp. of a head or figure with all detail blacked out in shadow leaving only the outline clearly defined "photograph in silhouette against a bright sky".
[2]outline vt (ca. 1790) 1: to draw the outline of
2: to indicate the principal features or different parts of "outlined their responsibilities"