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

Rice amino acids, avocado oil, glycerin, aloe, keratin Size: 6 fl. —Malia Griggs, Glamour, 2 May 2025

This moisturizing mask combines hydrolyzed collagen, wheat amino acids, and licorice root — an ideal combo after heated workouts and long plane rides. —Izzy Baskette, People.com, 1 May 2025

Leucine is an amino acid that directly triggers muscle protein synthesis and it can only be obtained through diet and supplementation. —Caroline Tell, Forbes.com, 29 Apr. 2025

The amino acid’s role in producing mood regulators means it could be associated with depression, for example. —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