noun

1. a digestive enzyme in the gastric juice of stomach secretions that catalyzes the splitting of proteins into smaller, more absorptive peptides
2. an extract of pepsin from the stomachs of calves, pigs, etc., formerly used as a digestive aid

Etymology: Ger: coined (1836) by T. Schwann (1810-82), Ger physiologist < Gr pepsis, digestion < peptein, earlier pessein, to cook, digest < IE base *pekw- > L coquere, cook