papillon (n.) Look up papillon at
1907, as a breed of dog, from French papillon, literally "butterfly," from Latin papilionem (nominative papilio) "butterfly," perhaps from a reduplicated form of PIE root *pal- "to touch, feel, shake."

The Latin word is cognate with Old English fifealde "butterfly," Old Saxon fifoldara, Old Norse fifrildi, Old High German vivaltra, German Falter. The dog so called for the shape of the ears.