■ noun
1》 an edible bulb used as a vegetable, having a pungent taste and smell and composed of several concentric layers.
2》 the plant that produces the ~, with spherical heads of greenish-white flowers. [ Allium cepa .]
Phrases
know one's ~s informal be very knowledgeable.
Derivatives
~y adjective
Origin
ME: from OFr. oignon , based on L. unio(n-) , denoting a kind of ~.