perineum (n.)

also perinaeum, "the region of the body between the anus and the genital organs" (jocularly called a taint), early 15c., from Medieval Latin perinaeon, Late Latin perineum, from Greek perinaion, perinaios, from peri "near" (see peri-) + inan "to carry off by evacuation," a word of unknown origin. Related: Perineal.