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

This research marks the first time scientists have identified the specific amino acids — arginine and tyrosine — that act as molecular glue, giving spider silk its legendary properties. —Mrigakshi Dixit, Interesting Engineering, 6 Feb. 2026

Two popular choices are the amino acid glycine and magnesium glycinate, a form of the mineral magnesium that's bonded to glycine, often to maximize effectiveness. —Sarah Garone, Health, 6 Feb. 2026

The amino acids required for collagen synthesis, particularly glycine, proline, and lysine, are readily available from a wide range of foods including eggs, fish, poultry, dairy products, legumes, soy foods and meat. —Leeann Weintraub, Daily News, 5 Feb. 2026

One risk factor for atherosclerosis is homocysteine, an amino acid naturally found in the body that can contribute to artery damage and blood clotting if its level rise too high. —Mara Santilli, Flow Space, 5 Feb. 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