There are two definitions found on Cheese Rennet :
cheese rennet - Collaborative International Dictionary of English v.0.48 :
Rennet \Ren"net\, n. [AS. rinnan, rennan, to run, cf. gerinnan to curdle, coagulate.
1. The inner, or mucous, membrane of the fourth stomach of the calf, or other young ruminant.
2. an infusion or preparation of the calf stomach lining, used for coagulating milk. The active principle in this coagulating action is the enzyme rennin. [Written also runnet.]
Rennet ferment (Physiol. Chem.), the enzyme rennin, present in rennet and in variable quantity in the gastric juice of most animals, which has the power of curdling milk. The enzyme presumably acts by changing the casein of milk from a soluble to an insoluble form.
Rennet stomach (Anat.), the fourth stomach, or abomasum, of ruminants.
1. The curd of milk, coagulated usually with rennet, separated from the whey, and pressed into a solid mass in a hoop or mold.
2. A mass of pomace, or ground apples, pressed together in the form of a cheese.
3. The flat, circular, mucilaginous fruit of the dwarf mallow
4. A low courtesy; -- so called on account of the cheese form assumed by a woman's dress when she stoops after extending the skirts by a rapid gyration. --De Quincey. --Thackeray.