Castor \Cas"tor\, n. [L. castor the beaver, Gr. ?; of uncertain origin.]

1. (Zo["o]l.) A genus of rodents, including the beaver. See Beaver.

2. Castoreum. See Castoreum.

3. A hat, esp. one made of beaver fur; a beaver.

I have always been known for the jaunty manner in which I wear my castor. --Sir W. Scott.

4. A heavy quality of broadcloth for overcoats.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Castor \Cast"or\, n. See Caster, a small wheel.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Castor \Cas"tor\, n. [L.]

(Astron.) the northernmost of the two bright stars in the constellation Gemini, the other being Pollux.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Castor \Cas"tor\, Castorite \Cas"tor*ite\, 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.

Source: Webster's Revised Unabridged Dictionary (1913)