epithelium

Etymology

From New Latin epithēlium, from Ancient Greek ἐπί (epí, “on, atop, epi-”) + θηλή (thēlḗ, “nipple”) + -ium (“aggregation”).

noun

1. (anatomy) A membranous tissue composed of one or more layers of cells which forms the covering of most internal and external surfaces of the body and its organs: internally including the lining of vessels and other small cavities, and externally being the skin.
   the passenger's roving eyes paused for a moment as he listened inwardly to a nether itch, which he supposed to be (correctly, thank Log) only a minor irritation of the epithelium. 1969, Vladimir Nabokov, Ada or Ardor, Penguin, published 2011, page 25