the clear digestive fluid produced by glands in the mucous membrane lining the stomach: it contains enzymes and hydrochloric acid and has a pH of c. 2.0
See gastric juice in American Heritage Dictionary 4
noun
The colorless, watery, acidic digestive fluid that is secreted by various glands in the mucous membrane of the stomach and consists chiefly of hydrochloric acid, pepsin, rennin, and mucin.