Where does “castor” come from?

Castor is from English caster, which is from English cast, ultimately deriving from the verb meaning to throw or direct.

castor (English): A hat made from the fur of the beaver; A heavy...

Definitions

A hat made from the fur of the beaver; A heavy...

Ancestry of “castor”, step by step

Step	Language	Word	Meaning
1	Old French	castor	beaver
2	Latin	Castor	Castor
3	Ancient Greek	Κάστωρ	Castor
4	Doric Greek	κάστον	—

Every word from Doric Greek κάστον →Every word from Ancient Greek Κάστωρ →Every word from Latin Castor →