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

In addition to essential vitamins and minerals, eggs contain omega-3 fatty acids. — Rachael Zimlich, Verywell Health, 26 Sep. 2026

Its conditioning blend of sensitive skin-friendly ceramides, fatty acids, cholesterol, and allantoin helps restore the skin barrier and stave off dryness all day long. — Kiana Murden, Vogue, 25 Sep. 2026

More of a milky toner than a traditional, liquid-y essence, this formula uses ceramides, fatty acids, and cholesterols (all lipids naturally found in the skin barrier) to make quick work of dryness. — Sarah Han, Allure, 24 Sep. 2026

Think of it as a brick wall, with tough skin cells as the bricks and lipids like ceramides, cholesterol and fatty acids as the mortar. — Hanna Wickes, Charlotte Observer, 17 Sep. 2026

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