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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.


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.


castor 1 British  
/ ˈkɑːstə /

noun

  1. a variant spelling of caster caster

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Castor 2 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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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


Etymology

Origin of castor1

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

Origin of Castor2

Named after Castor; 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.

The invasive species they brought — like black mustard, tree tobacco and castor bean — slowly crept into the ecosystem.

From Los Angeles Times • Dec. 14, 2024

Those oils could replace the reliance of growing dangerous crops, like castor.

From Science Daily • Apr. 30, 2024

Look for products that contain petroleum jelly, castor oil and glycerin, Rogers said.

From Seattle Times • Feb. 5, 2024

This is, in some sense, castor oil to swallow.

From Washington Post • Feb. 28, 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