A brief outline or cursory description, as in Let me give you a thumbnail sketch of the situation. This idiom alludes to drawing a picture no larger than a thumbnail. [Mid-1800s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
How to use thumbnail sketch in a sentence
Well, give me in a thumbnail sketch, something about Mr. Jitkoff's background.Warren Commission (9 of 26): Hearings Vol. IX (of 15) | The President's Commission on the Assassination of President Kennedy
Cummings' life is scarcely even a sketch; at most it is a thumbnail sketch.Old Scores and New Readings | John F. Runciman
From the thumbnail sketch to the many variations of a conceptual scheme, one eliminating the other, many decisions are arrived at.The Civilization of Illiteracy | Mihai Nadin