< /ˌæb əˈmeɪ sə/.
- the fourth or true stomach of cud-chewing animals, lying next to the omasum.
- the fourth and last compartment of the stomach of ruminants, which receives and digests food from the psalterium and passes it on to the small intestine
- The fourth division of the stomach in ruminant animals, and the only one having glands that secrete acids and enzymes for digestion. It corresponds anatomically to the stomachs of other mammals. See more at ruminant.