Hai Collection, Lower Volume
Radical: Tooth (chǐ)
Kangxi stroke count: 25
Page 1535, Entry 23
Tang Rhymes (Tangyun), Collected Rhymes (Jiyun), Dictionary of Rhymes (Yunhui), and Orthodox Rhymes (Zhengyun) state the pronunciation is yi (falling tone).
Shuowen Jiezi states it refers to the cud of a deer or elk.
Erya: Explanation of Beasts (Erya) states: The cud of an elk or deer is called yi.
Commentary: In the region east of the Yangtze River, the throat is called yi. Yi refers to the location where food is stored.
Guangyun states: To swallow fodder and regurgitate it to chew again.
Additionally, according to Guangyun, pronounced yi (entering tone); according to Collected Rhymes (Jiyun), pronounced yi (entering tone).
Additionally, according to Collected Rhymes (Jiyun), pronounced yi (falling tone). The meanings are the same.