castor

¹ American  

[kas-ter, kah-ster] / ˈkæs tər, ˈkɑ stər /

noun

1. 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.

2. a hat made of beaver or rabbit fur.

3. a heavy woolen cloth used mainly for coats.

4. a beaver.

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Castor ² American  

[kas-ter, kah-ster] / ˈkæs tər, ˈkɑ stər /

noun

Astronomy.

1. a star of the second magnitude in the constellation Gemini, the more northerly of the two bright stars in this constellation.

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Castor ¹ British  

/ ˈkɑːstə /

noun

1. 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

2. classical myth See Castor and Pollux

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castor ² British  

/ ˈkɑːstə /

noun

1. a variant spelling of caster caster

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castor ³ British  

/ ˈkɑːstə /

noun

1. the brownish aromatic secretion of the anal glands of a beaver, used in perfumery and medicine

2. the fur of the beaver

3. a hat made of beaver or similar fur

4. a less common name for beaver 1

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Castor Scientific  

/ kăs′tər /

1. A bright multiple star in the constellation Gemini, with a combined apparent magnitude of 0.08. Scientific name: Alpha Geminorum.

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Etymology

Origin of castor¹

1350–1400; Middle English < Latin < Greek kástōr beaver

Origin of Castor²

Named after Castor; see Castor and Pollux

Example Sentences

India mainly exports rice, shrimp, honey, vegetable extracts, castor oil and black pepper, while the US sends almonds, walnuts, pistachios, apples and lentils.

From BBC • Mar. 30, 2025

Around 90% of oil is valuable for industrial uses in crops like castor beans, Bates said.

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

Without a word, a somber woman slid the glass aside and handed each of us a large cup of castor oil.

From "Tasting the Sky" by Ibtisam Barakat