A medulla (/mɪˈdʌlə/; plural medullas or medullae) is the middle of something. The word came to English and ISV from Latin, where it means marrow (and came from medius, middle). Its anatomical uses include: A medulla (/mɪˈdʌlə/; plural medullas or medullae) is the middle of something. The word came to English and ISV from Latin, where it means marrow (and came from medius, middle). Its anatomical uses include: