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

According to Jonathan Rasouli, MD, a neurosurgeon at Northwell Health’s Staten Island University Hospital, fatty dairy products contain nutrients such as vitamin K2, calcium, and certain fatty acids that may support brain health. —Julia Ries Wexler, Health, 9 Jan. 2026

The arrangement and length of fatty acid chains also influence how our body processes fats. —Lauren J. Young, Scientific American, 7 Jan. 2026

This bar delivered thanks to its rich lather and moisturizing texture, a result of the lauric acid (which is a fatty acid that helps fight germs and emulsify the hard bar into a big, fluffy lather) baked in the soap. —Olivia Rose Rushing, InStyle, 7 Jan. 2026

Krill oil is one of the best sources of omega-3 fatty acids that offer health benefits for the heart, joints, and immune system. —Bestreviews, Chicago Tribune, 7 Jan. 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