n. [ L. castor the beaver, Gr. &unr_;; of uncertain origin. ] 1. (Zool.) A genus of rodents, including the beaver. See Beaver. [ 1913 Webster ]

2. Castoreum. See Castoreum. [ 1913 Webster ]

3. A hat, esp. one made of beaver fur; a beaver. [ 1913 Webster ]

I have always been known for the jaunty manner in which I wear my castor. Sir W. Scott. [ 1913 Webster ]

4. A heavy quality of broadcloth for overcoats. [ 1913 Webster ]

n. [ L. ] (Astron.) the northernmost of the two bright stars in the constellation Gemini, the other being Pollux. [ 1913 Webster ]

n. See Caster, a small wheel. [ 1913 Webster ]

[ Castor and Pollux were twin sons of Jupiter and Leda. ] (Naut.) See Saint Elmo's fire, under Saint. [ 1913 Webster ]

(Bot.) The bean or seed of the castor-oil plant (Ricinus communis, or Palma Christi.) [ 1913 Webster ]

n. [ L. See Castor. ] A peculiar bitter orange-brown substance, with strong, penetrating odor, found in two sacs between the anus and external genitals of the beaver; castor; -- used in medicine as an antispasmodic, and by perfumers. [ 1913 Webster ]

n. a natural family comprising the beavers.
Syn. -- family Castoridae. [ WordNet 1.5 ]

n. [ From 1st Castor. ] (Chem.) A white crystalline substance obtained from castoreum. [ 1913 Webster ]

{ } n. [ The minerals castor and pollux were so named because found together on the island of Elba. See Castor and Pollux. ] (Min.) A variety of the mineral called petalite, from Elba. [ 1913 Webster ]

n. a genus of extinct beavers of the Pleistocene; of eastern and southern U.S.
Syn. -- genus Castoroides. [ WordNet 1.5 ]