Webster’s Revised Unabridged Dictionary · 1913
Papilionaceous
Pa·pil′io·na′ceous (pȧ·pĭl′yō·nā′shŭs), a. 1. Resembling the butterfly.
2. (Bot.) (a) Having a winged corolla somewhat resembling a butterfly, as in the blossoms of the bean and pea. (b) Belonging to that suborder of leguminous plants (Papilionaceæ) which includes the bean, pea, vetch, clover, and locust.