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 amino acid is also incredibly beneficial for immune support, among other important functions in the body. —Kristine Thomason, Vogue, 22 Jan. 2026

The luxurious face lotion reduces the appearance of fine lines and wrinkles, thanks to a blend of vitamins, amino acids, botanical extracts, and more. —Ruby McAuliffe, InStyle, 21 Jan. 2026

Lamb provides protein and nine amino acids that support muscle recovery, repair, and development. —Mark Gurarie, Verywell Health, 21 Jan. 2026

Some studies suggest protein powders may be absorbed more quickly than whole-food sources, but whole foods tend to release amino acids more steadily and come with other nutrients that support how the body uses protein overall. —Deirdre Bardolf, FOXNews.com, 20 Jan. 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