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

That extra nourishment and moisture is thanks mostly to the omega’s long-chain fatty acids, which act primarily on the surface of the hair, protecting against friction and heat. —Philipp Wehsack, Vogue, 2 Sep. 2025

After 12–24 hours in the fridge, the full-bodied cold brew is ready to drink with no traces of fatty acids or bitter oils. —Mark Marino, Bon Appetit Magazine, 29 Aug. 2025

Key Takeaways Flaxseed's nutrients, such as dietary fiber, lignans, and omega-3 fatty acids, have been found to help manage blood lipid levels and lower high blood pressure. —Brittany Lubeck, Verywell Health, 27 Aug. 2025

Rich in fatty acids and protective ceramides, its formula strengthens the cuticle, smooths frizz, and leaves fragile strands looking fuller and less brittle over time. —Malia Griggs, Glamour, 25 Aug. 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