small, fast type of dog, c. 1600, probably from whip (v.) in the sense of "move quickly" + diminutive suffix -et. Used earlier (1540s) in reference to "a brisk, nimble woman."
Entries linking to whippet
whip v.
mid-13c., wippen "flap violently," not in Old English, of uncertain origin, ultimately from Proto-Germanic *wipjan "to move back and forth" (source also of Danish vippe "to raise with a swipe," Middle Dutch, Dutch wippen "to swing," Old High German wipf "swing, impetus"), from PIE root *weip- "to turn, vacillate, tremble." "The senses of both [noun and verb] no doubt represent several independent adoptions or formations" [OED]. The cookery sense is from 1670s. Related: Whipped; whipping. Whip snake first recorded 1774, so called for its shape.
-et
word-forming element, originally a diminutive suffix but not now always felt as one, Middle English, from Old French -et (fem. -ete; Modern French -et, -ette), from Vulgar Latin *-ittum/*-itta (source also of Spanish -eto/-eta, Italian -etto/-etta), of unknown origin. The French forms are reduced to -et in English, but later borrowings of French words in -ette tend to keep that ending.