- valve
- late 14c., "one of the halves of a folding door," from L. valva "section of a folding or revolving door," lit. "that which turns," related to volvere "to roll" (see vulva). Sense extended 1615 to "membranous fold regulating flow of bodily fluids;" 1659 to "mechanical device that works like a valve;" and 1661 in zoology to "halves of a hinged shell."