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

Proteins are made of amino acids and are needed to build and repair tissues and make important compounds like enzymes and hormones. — Jillian Kubala, HEALTH, 7 Aug. 2026

At above 25 individual amino acid changes, the chances of producing a viable virus are essentially zero. — ArsTechnica, 6 Aug. 2026

The dean of the USC Leonard Davis School of Gerontology was very familiar with this particular short chain of amino acids. — Los Angeles Times, 6 Aug. 2026

Exercise helps to direct dietary amino acids toward building and repairing muscle instead of leaving excess amino acids to be processed by the body, the researchers noted. — Khloe Quill, FOXNews.com, 3 Aug. 2026

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