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

Semax, a peptide containing seven amino acids, has been studied for its potential effects on the central nervous system. — Jacqueline Howard, CNN Money, 31 July 2026

For Americans who are less sedentary, Lamming notes athletes appear to be protected from the downsides of high protein intake because exercise sends extra amino acids into muscle instead of pathways linked to disease. — Antonio Pequeño Iv, Forbes.com, 31 July 2026

The review found that eating less protein, or less of certain amino acids that make up protein, may turn on body processes linked to healthier aging, as well as metabolism, the process by which the body turns food and drinks into energy. — ABC News, 31 July 2026

Encapsulated in exosome technology for precise delivery, the foundation also contains peptides, biocompatible pigments and amino acid powders. — Kathryn Hopkins, Footwear News, 31 July 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