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

Chia seeds are an excellent source of minerals, like magnesium, selenium, manganese, and copper, as well as healthy fats, like alpha-linolenic acid (ALA), a type of omega-3 fatty acid. —Jillian Kubala, Health, 12 Nov. 2025

This type of fatty acid is digested differently, which may be one reason it's touted as a healthy fat. —Patty Weasler, Verywell Health, 10 Nov. 2025

Bar soap contains fatty acids that react with certain minerals, especially those in hard water. —Gabi De La Rosa, Southern Living, 6 Nov. 2025

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

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