ruminate (v.)youdaoicibaDictYouDict[ruminate 词源字典]
1530s, "to turn over in the mind," also "to chew cud" (1540s), from Latin ruminatus, past participle of ruminare "to chew the cud; turn over in the mind," from rumen (genitive ruminis) "gullet," of uncertain origin. Related: Ruminated; ruminating.[ruminate etymology, ruminate origin, 英语词源]