Rennet /(r?n"n?t)/

Ren·net

Rennet

n.
  1. A name of many different kinds of apples. Cf. Reinette. (Bot.)

Rennet

n.
  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.

Phrases & Compounds
Cheese rennet
See under Cheese.
Rennet ferment
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
the fourth stomach, or abomasum, of ruminants.