peptide

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”).

noun

1. (organic chemistry) Any of a class of organic compounds consisting of various numbers of amino acids in which the amine of one is reacted with the carboxylic acid of the next to form an amide bond.
   When it’s digested, its long amino-acid chains are first broken down into smaller fragments, or peptides. It turns out that many hormones and drugs are also peptides, and a number of casein peptides do affect the body in hormone-like ways. 2004, Harold McGee, chapter 1, in On Food and Cooking: The Science and Lore of the Kitchen, Scribner
2. (chemistry) The peptide bond itself.