castor

plural castors

1. countableuncountableA hat made from the fur of the beaver.

   I have been always noted for the jaunty manner in which I wear my castor—[…]

   1826, [Walter Scott], chapter V, in Woodstock; Or, The Cavalier. […], volume I, Edinburgh: […] [James Ballantyne and Co.] for Archibald Constable and Co.; London: Longman, Rees, Orme, Brown, and Green, →OCLC, page 135

   Synonyms: beaver, castoreum

2. countableuncountableA heavy quality of broadcloth for overcoats.

   Synonyms: beaver

3. countableuncountableCastoreum (bitter exudate of mature beavers).
4. countableuncountableAny of various nymphalid butterflies of the genus Ariadne, of Africa and Asia.

1. uncountablechemistryA variety of petalite found in Elba.

   Synonyms: castorite

plural castors

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

      Mrs. Hussey soon appeared, with a mustard-pot in one hand and a vinegar-cruet in the other, having just broken away from the occupation of attending to the castors, and scolding her little black boy meantime.

      1851 November 14, Herman Melville, “The Ramadan”, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, →OCLC, page 92

1. Greekhuman sciencesOne of the Dioscuri
2. astronomyA double star in the constellation Gemini; alpha (α) Geminorum.
3. A village and civil parish in city of Peterborough district, Cambridgeshire, England (OS grid ref TL1298).
4. A town in the County of Paintearth, Alberta, Canada. From French castor (“beaver”).
5. A village in Bienville Parish, Louisiana, United States. From French castor (“beaver”).
6. A surname.