Main Entry: on·ion

Pronunciation: \ˈən-yən\

Function: noun

Etymology: Middle English, from Anglo-French oignon, from Latin union-, unio

Date: 14th century

1 : a widely cultivated Asian herb (Allium cepa) of the lily family with pungent edible bulbs; also : its bulb
2 : any of various plants of the same genus as the onion

— on·iony \-yə-nē\ adjective