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

Called Råvaror, the new collection includes 20 new products: a daybed, a sofa, tables, a mini kitchen, storage solutions on castors, textiles, and lighting. Elizabeth Gulino, House Beautiful, "Ikea’s New Packable Furniture Will Change Your Life," 24 July 2019 Olérys and Laugier manufactory sugar castor from Moustiers (c. 1750) Photo: Sidney R. Knafel Collection French faience has its roots in Italy, its name derived from the northern Italian city Faenza, an important producer of majolica. Barrymore Laurence Scherer, WSJ, "‘Masterpieces of French Faience: Selections From the Sidney R. Knafel Collection’ Review: Not Dishwasher Safe," 1 Jan. 2019 Star players include collagen-boosting raspberry seed oil, moisturizing castor seed oil, and antioxidant-heavy camellia japonica seed oil. Sophie Wirt, Allure, "Exclusive: Wander Beauty Launches Glow Ahead, Its First-Ever Facial Oil," 17 July 2018 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

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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Last Updated

30 Jul 2019

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Time Traveler for castor

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

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More from Merriam-Webster on castor

Rhyming Dictionary: Words that rhyme with castor

Spanish Central: Translation of castor Encyclopedia article about castor

Comments on castor

What made you want to look up castor? Please tell us where you read or heard it (including the quote, if possible).


a period when something is suspended

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