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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Tatcha’s creamy cleanser gently washes the day away with an amino acid base, while Okinawa algae and hyaluronic acid deeply nourish the skin and replenish its water reserve. — Lauren Valenti, Vogue, 29 Oct. 2026 When scientists synthesize spider silk in the lab, using the exact sequence of amino acids to build a spidroin protein, the resulting silk is not as strong as natural silk. — Yasemin Saplakoglu, Quanta Magazine, 28 Oct. 2026 Peptides are small chains of amino acids, which are the building blocks of proteins. — Adam Kovac, Scientific American, 28 Oct. 2026 Peptides are strings of amino acids, shorter than proteins, that can exert powerful effects in the body. — Sydney Lupkin, NPR, 28 Oct. 2026 See All Example Sentences for amino acid

Word History

First Known Use

1897, in the meaning defined above

Time Traveler
The first known use of amino acid was in 1897

Rhymes for amino acid

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Browse Nearby Words

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amino acid
aminoaciduria
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Cite this Entry

“Amino acid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/amino%20acid. Accessed 30 Oct. 2026.

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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

More from Merriam-Webster on amino acid

Britannica.com: Encyclopedia article about amino acid

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