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

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

In particular, the standard amino acid tryptophan was swapped for a synthetic counterpart called azatryptophan. — Mrigakshi Dixit, Interesting Engineering, 21 Sep. 2026

Some incredibly successful drugs such as insulin and the weight loss drugs Wegovy and Zepbound are peptides, short chains of amino acids that can be made into countless configurations. — Jonathan Fahey, Los Angeles Times, 18 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