amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : any of the various amino acids having the amino group in the alpha position that are the chief components of proteins and are synthesized by living cells or are obtained as essential components of the diet

Examples of amino acid in a Sentence

Recent Examples on the Web

Hyaluronic acid, niacinamide, amino acids Fragrance: Fragrance-free Size: 1.7 fl. —Alanna Martine Kilkeary, Glamour, 1 May 2025

Peptides are chains of amino acids, which are the building blocks of proteins that are essential for the skin.1 In addition to being naturally produced by the body, peptides are also used in topical skin care products like serums, moisturizers, sunscreens, and more, plus oral supplements. —Cristina Mutchler, Verywell Health, 25 Apr. 2025

The vegan diet paid special attention to the amino acid content, to ensure the plant proteins were complete and comparable to the animal sources. —New Atlas, 24 Apr. 2025

Newsletter Sign up for our email newsletter for the latest science news L-tyrosine, also simply known as tyrosine, is an amino acid and a building block our bodies use to produce protein. —Sean Mowbray, Discover Magazine, 22 Apr. 2025

Word History

First Known Use

1897, in the meaning defined above

Rhymes for amino acid

• antacid
• placid

Kids Definition

amino acid

noun

ami·​no acid

ə-ˈmē-nō-

: any of numerous acids that include some which are the building blocks of proteins and are made by living cells from simpler compounds or are obtained in the diet

Medical Definition

amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : alpha-amino acid