castor
noun
Also a brownish, unctuous substance with a strong, penetrating odor, secreted by certain glands in the groin of the beaver, used in medicine and perfumery.
castor
1 American
[kas-ter, kah-ster]
/ ˈkæs tər, ˈkɑ stər /
noun
-
castors
plural
-
Also a brownish, unctuous substance with a strong, penetrating odor, secreted by certain glands in the groin of the beaver, used in medicine and perfumery.
-
a hat made of beaver or rabbit fur.
-
a heavy woolen cloth used mainly for coats.
-
a beaver.
Castor
2
American
[kas-ter, kah-ster]
/ ˈkæs tər, ˈkɑ stər /
noun
Astronomy.
Castor
1
British
/ ˈkɑːstə /
noun
-
the second brightest star, Alpha Geminorum, in the constellation Gemini: a multiple star consisting of six components lying close to the star Pollux. Distance: 52 light years
-
classical myth See Castor and Pollux
castor
2
British
/ ˈkɑːstə /
noun
castor
3
British
/ ˈkɑːstə /
noun
-
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
Castor
Scientific
/ kăs′tər /
Other Word Forms
Noun Inflected Forms
Etymology
Origin of castor1
1350–1400; Middle English < Latin < Greek kástōr beaver
Origin of Castor2
Named after Castor; see Castor and Pollux
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Ricin is a highly toxic poison naturally derived from castor oil plants.
From BBC ● Oct. 29, 2024
The modified Arabidopsis overcame metabolic bottlenecks and produced significant amounts of an oil similar to castor oil that it doesn't naturally produce.
From Science Daily ● Apr. 30, 2024
Newer products include a hair strengthening collection with biotin and Jamaican castor oil, and a wig care collection that uses apple cider vinegar to remove build-up from weaves and wigs.
From Los Angeles Times ● Nov. 2, 2023
Other formulas are based on plant oils, including castor bean, cedarwood, clove and peppermint.
From Seattle Times ● May 20, 2023
“Why, Daisy, I couldn’t take any of that nasty stuff. All you think about is castor oil. If I even mash my finger, the first thing you do is grab that old castor oil bottle.”
From "Summer of the Monkeys" by Wilson Rawls
Castor cited what she described as reckless attacks on other renewable-energy projects—such as wind power—and the independence of the NRC.
From The Wall Street Journal ● Jan. 8, 2026
Tampa Mayor Jane Castor called the incident "devastating" in a statement on X.
From BBC ● Nov. 8, 2025
The highest ever Powerball jackpots were both won in California — in Nov. 2022 when Edwin Castor of Altadena purchased a ticket worth $2.04 billion and in Oct.
From Los Angeles Times ● Aug. 25, 2025
"I’ve said many times that if you want to pick a fight with Mother Nature, she’s winning 100 percent of the time," Tampa Mayor Jane Castor said in a press conference Tuesday.
From Salon ● Oct. 9, 2024
He showed up as promised, and delivered his panegyric—but in the course of it, he included a decorative digression, as might have been quite normal practice, in praise of the twin demigods Castor and Pollux.
From "Words Like Loaded Pistols" by Sam Leith
As for the metallic pepperpot-shaped aliens, created by designer Raymond Cusick, Ms Webb remembers rehearsals with actors "trolleying" around on castors in just the bottom halves of the characters that would become The Doctor's nemesis.
From BBC ● Dec. 21, 2023
It's odd at first; Stewart seems dazed by the noisiness of the production, to be moving as if on castors.
From Los Angeles Times ● Nov. 4, 2016
The sculptural giltwood pedestal includes leopard masks above three paw feet that conceal recessed brass castors.
From Architectural Digest ● Jan. 14, 2015
The blocks and castors terminating the legs are modern replacements and, like the French set, they are neither glamorous enough to satisfy buyers looking for trophies nor sought after as furniture to live with.
From New York Times ● Jul. 22, 2011
After an hour had passed, Mrs. Mitchell placed her shoulder against the chiffonier, that rolled easily on its castors, and she slipped behind it.
From A Speckled Bird by Augusta J. Evans Wilson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
