Ŏn'ion, n.

(ŭn'yun), n. [Fr. oignon, ognon, Pr. uignon, ignon, from Lat. unio, a kind of single onion, the bulb of which was formed of a single piece, from unio, oneness, unity, from unus, one.] (Bot.) A plant of the genus Allium (A. cepa); also, its bulbous root, much used as an article of food.