castor

Etymology 1

From Middle French castor, from Old French castor (“beaver”), from Latin castor (“beaver”), from Ancient Greek κάστωρ (kástōr), from Doric Greek κάστον (káston, “wood”).

noun

1. A hat made from the fur of the beaver.
2. A heavy quality of broadcloth for overcoats.
3. Castoreum (bitter exudate of mature beavers).
4. Any of various nymphalid butterflies of the genus Ariadne, of Africa and Asia.

Etymology 2

Named from Greek mythology; see Castor and Pollux. The name pollux was given to another mineral with which it was always found.

noun

1. (mineralogy) A variety of petalite found in Elba.

Etymology 3

Alternative spelling of caster, via cast + -or (the Latinate varient of -er).

noun

1. (especially UK) Alternative spelling of caster, especially in its senses
   1. A pivoting roller attached to the bottom of furniture to allow it to be moved.
   2. A container with a perforated cap for sprinkling its contents, especially salt, pepper, etc.