1570s (adj.), "draining out;" 1610s (n.), in anatomy, "an emulgent vessel," from Latin emulgentem (nominative emulgens), present participle of emulgere "to milk out, drain out, exhaust," from assimilated form of ex "out" (see ex-) + mulgere "to milk" (from PIE root *melg- "to rub off; to milk"). Related: Emulgence.