castor: Meaning and Definition of

cas•tor

1. a brownish, unctuous substance with a strong, penetrating odor, secreted by certain glands in the groin of the beaver, used in medicine and perfumery.
2. a hat made of beaver or rabbit fur.
3. a heavy woolen cloth used mainly for coats.
4. a beaver.

cas•tor

1. caster (defs. 2–5).

Cas•tor

1. a star of the second magnitude in the constellation Gemini, the more northerly of the two bright stars in this constellation.