fatty acid

noun

1

: any of numerous saturated aliphatic monocarboxylic acids C_nH_2n+1COOH (such as acetic acid) including many that occur naturally usually in the form of esters in fats, waxes, and essential oils

2

: any of the saturated or unsaturated monocarboxylic acids (such as palmitic acid) usually with an even number of carbon atoms that occur naturally in the form of glycerides in fats and fatty oils

Examples of fatty acid in a Sentence

Recent Examples on the Web

The experiments showed that putting monounsaturated fatty acids on the skin could help hair grow, the researchers noted. —Angelica Stabile, FOXNews.com, 2 Nov. 2025

Almonds and pistachios both contain soluble fiber, a type of fiber that is broken down by bacteria in the large intestine, releasing short-chain fatty acids (SCFAs). —Jillian Kubala, Health, 30 Oct. 2025

Then, the scientists tested whether topical fatty acids could drive regrowth, without the need to induce irritation or injury. —New Atlas, 29 Oct. 2025

Dry lower-leg skin in African-American women is distinctive for its downregulation of several free fatty acids. —Rafil Kroll-Zaidi, Harpers Magazine, 29 Oct. 2025

Word History

First Known Use

1838, in the meaning defined at sense 1

Rhymes for fatty acid

• antacid
• placid

Kids Definition

fatty acid

noun

: any of numerous acids that contain only carbon, hydrogen, and oxygen and occur naturally in fats and various oils

Medical Definition

fatty acid

noun

1

: any of numerous saturated aliphatic acids C_nH_2n+1COOH (as lauric acid) containing a single carboxyl group and including many that occur naturally usually in the form of esters in fats, waxes, and essential oils

2

: any of the saturated or unsaturated organic acids (as palmitic acid) that have a single carboxyl group and usually an even number of carbon atoms and that occur naturally in the form of glycerides in fats and fatty oils