epithelium
noun [ C or U ] medical specialized uk/ˌep.ɪˈθiː.li.əm/ us/ˌep.ɪˈθiː.li.əm/ epithelia /ˌep.ɪˈθiː.li.ə/ /ˌep.ɪˈθiː.li.ə/
上皮，上皮组织
a layer of cells covering all the surfaces of the body except the interior of blood and lymph vessels