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

Warm milk delivers tryptophan, the amino acid your body converts into serotonin and melatonin. — Lauren Jarvis-Gibson july 25, Miami Herald, 25 July 2026

The researchers could take the output of the contact probability analysis for on- and off-target sites and compare them, identifying exactly which amino acids in Cas9 have altered contacts when there’s a mismatch between the guide RNA and the DNA. — ArsTechnica, 24 July 2026

As wellness clinics increasingly capitalize on the exploding interest in the chains of amino acids that promise everything from longevity to weight loss, a Washington Post investigation has found gaping holes in the nation’s regulatory system. — Lauren Weber, Washington Post, 24 July 2026

Recently, Overton has been involved in drafting new policies for the use of peptides, short chains of amino acids that are available on the gray market but that, in many cases, have scant scientific evidence to support their safety or efficacy. — Michael Scherer, The Atlantic, 24 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