the brownish aromatic secretion of the anal glands of a beaver, used in perfumery and medicine the fur of the beaver a hat made of beaver or similar fur - a less common name for
beaver 1 1
WordReference Random House Unabridged Dictionary of American English © 2026
cas•tor1
(kas′tər, kä′stər),USA pronunciation n.
cas•tor2 (kas′tər, kä′stər),USA pronunciation n.
Cas•tor (kas′tər, kä′stər),USA pronunciation n. [Astron.]
- Also, castoreum. a brownish, unctuous substance with a strong, penetrating odor, secreted by certain glands in the groin of the beaver, used in medicine and perfumery.
- Clothinga hat made of beaver or rabbit fur.
- Textilesa heavy woolen cloth used mainly for coats.
- a beaver.
- Greek kástōr beaver
- Latin
- Middle English 1350–1400
cas•tor2 (kas′tər, kä′stər),USA pronunciation n.
- caster (defs. 2–5).
Cas•tor (kas′tər, kä′stər),USA pronunciation n. [Astron.]
- Astronomya star of the second magnitude in the constellation Gemini, the more northerly of the two bright stars in this constellation.
- see Castor and Pollux named after Castor
Collins Concise English Dictionary © HarperCollins Publishers::
- a variant spelling of
caster 2