apodyterium n.

before vowels ap-, word-forming element meaning "of, from, away from; separate, apart from, free from," from Greek apo "from, away from; after; in descent from," in compounds, "asunder, off; finishing, completing; back again," of time, "after," of origin, "sprung from, descended from; because of," from PIE root *apo- "off, away" (source also of Sanskrit apa "away from," Avestan apa "away from," Latin ab "away from, from," Gothic af, Old English of "away from," Modern English of, off).

H.L. Mencken's invented proper word for "strip-tease artist," 1940, from Greek ekdysis "a stripping or casting off" (used scientifically in English from mid-19c. with reference to serpents shedding skin and molting birds or crustacea), from ekdyein "to put off one's clothes, take off, strip off" (contrasted with endyo "to put on"), from ek (see ex-) + dyein "enter, to dive; to plunge; get into, slip into, put on," which, according to Beekes, is "related to the rare Sanskrit verb upa-du- 'to put on' ...."