hop-o'-my-thumb

Etymology
From the idea that such a person could hop over somebody's thumb; in common use in the 16th century.

Noun

 * 1)  A very small person or creature.
 * 2) * 1830, Uncredited (John Poole), The New Monthly Magazine and Literary Journal, Part 1: Original Papers, page 81,
 * As to changing them for a pack of your little hop-o'-my-thumbs, no bigger than the one you lent me t'other night — ! [sic] suppose I should ask you to let me have the mare you rode to cover o'Thursday — and a clever mare she is,.

Usage notes
Notably used (from 1804) to translate the title of the French fairy tale Le Petit Poucet.