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

The Peptide-132 Hair Bond Repair Treatment uses a proprietary peptide complex, along with keratin, collagen, and amino acids, to repair damage, smooth frizz, and strengthen dry or overprocessed strands without weighing hair down. —Christa Joanna Lee, Allure, 18 June 2026

The protein and amino acids in eggs help provide the building blocks needed to produce keratin and collagen, which help strengthen hair and nails. —Olivia McIntosh, Martha Stewart, 17 June 2026

Creatine is a compound made from three amino acids that your body stores mostly in your muscles, with smaller amounts in your brain, according to Mayo Clinic. —Samantha Agate, Miami Herald, 16 June 2026

Tranexamic acid is an amino acid derivative that mitigates inflammation, prevents new dark spots from forming, fades existing ones, clears congestion, and enhances radiance. —Tamim Alnuweiri, InStyle, 16 June 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