noun (1)
cas·​tor | \ ˈka-stər How to pronounce castor (audio) \

Definition of castor

 (Entry 1 of 2)

2 : castoreum
3 : a beaver hat


noun (2)
Cas·​tor | \ ˈka-stər How to pronounce Castor (audio) \

Definition of Castor (Entry 2 of 2)

1 : one of the Dioscuri
2 : the more northern of the two bright stars in Gemini

Examples of castor in a Sentence

Recent Examples on the Web: Noun

The Pentagon said Wednesday that the letters sent there didn’t contain ricin, as initially believed, but instead contained castor seeds, from which the poison is derived. Nancy A. Youssef, WSJ, "Letters to Pentagon Held Castor Seeds, Not Ricin; Utah Man Is Held," 3 Oct. 2018 CoverGirl infused the formula with conditioning castor, jojoba, and sunflower seed oils. Shannon Barbour, The Cut, "CoverGirl’s New Lip Glosses Really Sparkle," 9 Apr. 2018 The castor wheels on the current prototype, which is slightly less than 5 feet long, allow the students to test it without snow; the final version would have skis underneath. Kathy Boccella,, "A sled for the blind? Students are making one at Bensalem High School," 3 Apr. 2018 One antidote: this spray loaded with oils including argan and castor. Dana Wood, WSJ, "Want Better Hair? Pay More Attention to Your Scalp," 22 Mar. 2018 Ancient Egyptian beauty rituals included nourishing skin with castor, sesame and moringa oils. Karina Hoshikawa, Teen Vogue, "Why I Love Skin Care," 31 Jan. 2018 Founded by a New Zealand soccer star and a clean-technology entrepreneur, Allbirds makes the sneakerlike shoes from wool and castor-bean oil. Nellie Bowles, The Seattle Times, "Latest Silicon Valley breakthrough: wool shoes," 14 Aug. 2017 The model shared her secrets: castor oil and Anastasia Beverly Hills Clear Brow Gel are her two best friends. De Elizabeth, Allure, "Model Scarlett Costello Opens Up About Her Unibrow," 10 July 2017 For Nearly Neons, a base of organic castor seed oil is triple milled with a blend of iron oxides, food-grade pigments and D&C Colorants. Sarah Wu, Teen Vogue, "Bite Beauty Launches The Nearly Neon Collection," 5 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'castor.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of castor

Noun (1)

14th century, in the meaning defined at sense 1

Noun (2)

15th century, in the meaning defined at sense 1

History and Etymology for castor

Noun (1)

Middle English, from Latin, from Greek kastōr, from Kastōr Castor

Noun (2)

Latin, from Greek Kastōr

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Time Traveler for castor

The first known use of castor was in the 14th century

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Rhyming Dictionary: Words that rhyme with castor

Spanish Central: Translation of castor Encyclopedia article about castor

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