|1.||an alliaceous plant, Allium cepa, having greenish-white flowers: cultivated for its rounded edible bulb|
|2.||the bulb of this plant, consisting of concentric layers of white succulent leaf bases with a pungent odour and taste|
|3.||any of several related plants similar to A. cepa, such as A. fistulosum (Welsh onion)|
|4.||slang (Brit) know one's onions to be fully acquainted with a subject|
|[C14: via Anglo-Norman from Old French oignon, from Latin unio onion, related to |
The Israelites in the wilderness longed for the "onions and garlick of Egypt" (Num. 11:5). This was the _betsel_ of the Hebrews, the Allium cepe of botanists, of which it is said that there are some thirty or forty species now growing in Palestine. The onion is "the 'undivided' leek, _unio_, _unus_, one."
see know one's stuff (onions).