thumbnail

noun

1. the nail of the thumb.
2. anything quite small or brief, as a small drawing or short essay.
3. Printing. a small, rough dummy.
4. Also called porkchop. Journalism, Printing. a half-column portrait in a newspaper.

adjective

5. quite small or brief; concise: a thumbnail description of Corsica.

verb (used with object)

6. to make a thumbnail sketch or description of.

noun

1. the nail of the thumb
2. (modifier) concise and briefa thumbnail sketch
3. computing a small image which can be expanded

n.c.1600, from thumb (n.) + nail (n.). Meaning “drawing or sketch of a small size” (though usually not lierally the size of a thumbnail) is from 1852.