Onion n. 1.(Bot.) A liliaceous plant of the genus Allium (Allium cepa), having a strong-flavored bulb and long hollow leaves; also, its bulbous root, much used as an article of food. The name is often extended to other species of the genus.
2.The flavor of an onion (1).
Onion fish (Zool.), the grenadier.
Onion fly (Zool.) a dipterous insect whose larva feeds upon the onion; especially, Anthomyia ceparum and Ortalis flexa.
Welsh onion. (Bot.) See Cibol. Wild onion (Bot.), a name given to several species of the genus Allium.
Welsh adj. (Sometimes written also Welch) Of or pertaining to Wales, or its inhabitants. Welsh flannel, a fine kind of flannel made from the fleece of the flocks of the Welsh mountains, and largely manufactured by hand.
Welsh glaive, or Welsh hook, a weapon of war used in former times by the Welsh, commonly regarded as a kind of poleax.
Welsh mortgage (O. Eng. Law), a species of mortgage, being a conveyance of an estate, redeemable at any time on payment of the principal, with an understanding that the profits in the mean time shall be received by the mortgagee without account, in satisfaction of interest.
Welsh mutton, a choice and delicate kind of mutton obtained from a breed of small sheep in Wales.
Welsh onion (Bot.), a kind of onion (Allium fistulosum) having hollow inflated stalks and leaves, but scarcely any bulb, a native of Siberia. It is said to have been introduced from Germany, and is supposed to have derived its name from the German term wälsch foreign.
Welsh parsley, hemp, or halters made from hemp. (Obs. & Jocular)
Welsh rabbit. See under Rabbit. 
