papillon (n.)

1907 as a breed of dog, from French papillon, literally "butterfly," from Latin papilionem (nominative papilio) "butterfly," which is perhaps from a reduplicated form of a PIE root *pl- "to fly, flutter." The Latin word is believed to be cognate with Old English fifealde, Old Saxon fifoldara, Old Norse fifrildi, Old High German vivaltra, German Falter "butterfly;" Old Prussian penpalo, Lithuanian piepala, Russian perepel "quail." The dog was so called for the shape of the ears. Middle English had papilloun "a butterfly," from Old French.