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

In their view, inorganic molecules might have reacted due to energy from the Sun or lightning strikes to form life’s building blocks, like amino acids. —Ars Technica, 14 Mar. 2025

For instance, one study evaluated a facial serum containing neuropeptides, proteins, amino acids, and marine extract. —Kathleen Ferraro, Verywell Health, 12 Mar. 2025

To determine the child’s age, scientists extracted a specific amino acid called hydroxyproline from collagen in the bones. —Sarah Kuta, Smithsonian Magazine, 10 Mar. 2025

High levels of this amino acid are known to increase the risk of coronary artery disease and blood clots, and can result from a diet deficient in folic acid or vitamin B12. —Neil Savage, Scientific American, 6 Mar. 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