Castor
What is castor?
Key facts
| Beaver | A beaver, as in sense 1a[1] |
|---|---|
| Castoreum | A brownish, unctuous substance secreted by certain glands in the groin of the beaver[1] |
| Hat | A hat made of beaver or rabbit fur[2] |
| Astronomy | The more northern of the two bright stars in Gemini[1] |
| Botany | The castor oil plant (Ricinus communis) and its seeds[3] |
Castor is an ambiguous word with several distinct meanings, including a beaver, castoreum, a hat made of beaver or rabbit fur, the brighter northern star in Gemini, and the castor oil plant (Ricinus communis). The intended meaning depends on context.
Context
Castor is a word with multiple meanings. It can mean a beaver, castoreum, a hat made of beaver or rabbit fur, or the brighter northern star in Gemini. In botany, castor refers to the castor oil plant (Ricinus communis) and its seeds, known as castor beans. These seeds are used to produce castor oil, and they are a type of beans. The intended meaning of castor depends on the context, whether zoology, astronomy, mythology, clothing, or botany [1]. Dictionary sources differ in which senses they list, and some list 'caster' as a variant spelling for the furniture-wheel sense, which is a common confusion [2].
Documented claims
Questions and answers
What does a castor mean?
Castor has several meanings, including a beaver, castoreum, a hat, a star in Gemini, and the castor oil plant. The meaning depends on context [1].
Why is a beaver called castor?
The word castor comes from the Latin and Greek names for beaver, and it is used to refer to the animal itself or the substance castoreum [1].
What is a castor used for?
In botany, castor refers to the castor oil plant, whose seeds are used to make castor oil. In other contexts, castor can refer to a hat or a star [3].
Sources
- CASTOR Definition & Meaning — merriam-webster.com (retrieved August 3, 2026)
- CASTOR Definition & Meaning — dictionary.com (retrieved August 3, 2026)
- Castor Definition — yourdictionary.com (retrieved August 3, 2026)