me·di·al
adjective/ˈmiːdiəl/
/ˈmiːdiəl/
(specialist)- located in the middle, especially of the body or of an organ
（身体或器官等）内侧的，近中的 Word Originlate 16th cent. (in the sense ‘relating to the mean or average’): from late Latin medialis, from Latin medius ‘middle’.