The abomasum, also known as the maw, rennet-bag, or reed tripe, is the fourth and final stomach compartment in ruminants. It secretes rennet, which is used in cheese creation.
The word abomasum is from New Latin and it was first used in English in 1706. It comes from Latin ab- + omasum "intestine of an ox," and it is possibly from the Gaulish language.