also: しゅうい · すうい
abomasum
The fourth stomach compartment of ruminants; a technical term used in veterinary medicine and animal science.
The cow's abomasum is also called the fourth stomach.
Mixed kana-kanji spelling; less common but still used.
From 皺 (wrinkle) + 胃 (stomach), referring to the folded lining of the abomasum.