castor oil

noun

: a pale viscous fatty oil from castor beans used especially as a cathartic and as a lubricant and plasticizer

Examples of castor oil in a Sentence

Recent Examples on the Web

Use castor oil, coffee grounds, or garlic and chili pepper spray to deter moles. — Nadia Hassani, The Spruce, 7 Mar. 2026

Don’t forget its other main ingredient, castor oil, which is known to help with hair growth. — Katie Decker-Jacoby, StyleCaster, 18 Mar. 2026

Shea butter, cocoa butter, and castor oil are deeply hydrating and can help define your curl pattern. — Aimee Simeon, Glamour, 7 May 2026

It’s made with ingredients like shea butter and castor oil to help keep lashes strong and hydrated, even through all-day wear. — Madeline Merinuk, PEOPLE, 24 June 2026

Word History

Etymology

probably from its former use as a substitute for castoreum in medicine

First Known Use

1746, in the meaning defined above

Rhymes for castor oil

• aerofoil
• cinquefoil
• hydrofoil
• quatrefoil
• airfoil
• benzoyl
• despoil
• embroil
• etoile
• gargoyle
• recoil
• subsoil

Kids Definition

castor oil

noun

: a pale thick oil obtained from castor beans and used chiefly as a lubricant or a laxative

Medical Definition

castor oil

noun

: a pale viscous fatty oil from castor beans used especially as a cathartic or lubricant