Yes, it's rennet in English and causes the cheese to set-up (all over not just the skin on the top). It's an "old fashioned" American dessert, rennet pudding.
You can buy it on-line in the states in different forms, vegetable or animal. I bought the animal cuajo here, which is "something" to do with the stomach of a cow. I am learning to make my own mozzarella cheese. 1st I need to make homemade buttermilk, because I can't find that here!
Thanks again for your help.