medulla (n.)youdaoicibaDictYouDict[medulla 词源字典]
hindmost segment of the brain, 1650s, from Latin medulla, literally "marrow," also "pith of plants," of unknown origin, perhaps related to or influenced by medius "middle" (but compare also Old Irish smiur, Welsh mer "marrow"). The word was used in the Latin senses in Middle English. Related: Medular; medullary.[medulla etymology, medulla origin, 英语词源]