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

Traditional biosignature approaches focus on searching for specific compounds, such as certain amino acids or lipid structures, or for chiral preferences, like left-handedness. —Amirali Aghazadeh, The Conversation, 12 Dec. 2025

These line-smoothing moisturizers are not only packed with collagen, but also skin-boosting ingredients like peptides and amino acids that work together to make complexion appear more bouncy and resilient. —Deanna Pai, Glamour, 11 Dec. 2025

Pre-workout supplements combine various amino acids and stimulants to help boost energy and performance during your workout. —Carley Millhone, Health, 11 Dec. 2025

Tyrosine is an amino acid that separates from proteins in the cheese as the cheese breaks down during aging. —Katie Rosenhouse, Southern Living, 5 Dec. 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