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

It’s also loaded with botanicals, including allantoin and the star ingredient, birch tree sap, which is packed with natural moisturizing factors like amino acids and lactic acid to bolster skin barrier health. — Kiana Murden, Vogue, 25 Sep. 2026

Protein is made from amino acids, including nine essential ones the body can’t produce on its own. — Ryan Brennan, Miami Herald, 23 Sep. 2026

Protein is built from amino acids, nine of which the body can’t make on its own. — Ryan Brennan, Fort Worth Star-Telegram, 23 Sep. 2026

This lightweight serum delivers antioxidant-rich macroalgae, nourishing amino acids, and soothing blue flower linseed to the delicate eye contour area to promote smoother, firmer skin. — Mariana Best, PEOPLE, 23 Sep. 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