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

Our editors loved the conditioning feel of its formula, which is infused with shea butter and castor oil, and found that the brush’s dense bristles grabbed every little lash. — Micaela English, Glamour, 14 Aug. 2026

How to Use Castor Oil for Hair From buying hair products that contain castor oil to creating your own DIY castor oil treatment, there are a number of ways to incorporate the ingredient into your haircare routine. — Nicole Catanese, InStyle, 12 Aug. 2026

Some people may develop contact dermatitis or hair felting after using castor oil. — Hannah Harper, HEALTH, 1 Aug. 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