English Reference

Word

peptide

Phoneticspep·tide

US/ˈpɛpˌtaɪd/

UK/pˈɛptaɪd/

Definitions

01chemical compound

C1 · Science

n. a small molecule made of amino acids that are linked together.

n. a compound consisting of two or more amino acids linked in a chain, the carboxyl group of each acid being joined to the amino group of the next by a bond.

“The scientist studied how the peptide chain folds into a specific shape.”

“Short-chain peptides act as signaling molecules in the body, regulating various physiological processes including hormone release and immune response.”

Technical

Synonyms

polypeptidemolecule

02performance-enhancing drug

C2 · Sport

n. a type of supplement or drug used by athletes to build muscle or recover faster.

n. a euphemistic reference to synthetic performance-enhancing drugs, often marketed for muscle growth or anti-aging properties.

“He was banned from the competition after testing positive for banned peptides.”

“The rise of underground labs selling unapproved peptides has created significant challenges for anti-doping agencies worldwide.”

Informal · Slang

Synonyms

Real-World Examples

“And some are injected - like peptides, a type of protein that's becoming increasingly popular online.”
BBC News · 18 Aug 2026
“Scientists had generally thought that agouti-related peptide (AgRP) neurons, which are well known for stimulating hunger, worked mainly against weight loss.”
ScienceDaily · 20 Aug 2026

Etymology

From peptone, partially hydrolyzed protein, or German Peptid, from German Pepton, from Ancient Greek πεπτόν (peptón, “cooked, digested”) derived from πέπτω (péptō, “soften, ripen, boil, cook, bake, digest”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Domain

Chemistry

This entry

Level
C1 · Advanced
Frequency
Frequent
Updated

Scan code

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English Reference