prostate (n.)

1640s, from Middle French prostate, from Medieval Latin prostata "the prostate," from Greek prostates (aden) "prostate (gland)," from prostates "leader, ruler, guardian; one standing in front," from proistanai "set before," from pro "before" (from PIE root *per- (1) "forward," hence "in front of, before") + histanai "cause to stand," from PIE root *sta- "to stand, make or be firm." So called from its position at the base of the bladder.