n.
Pronunciation: ' valv
Function: noun
Etymology: Latin valva; akin to Latin volvere to roll ― more at VOLUBLE
Date: 14th century
1 archaic : a leaf of a folding or double door
2 [New Latin valva, from L] : a bodily structure (as the mitral valve) that closes temporarily a passage or orifice or permits movement of fluid in one direction only
3 a : any of numerous mechanical devices by which the flow of liquid, gas, or loose material in bulk may be started, stopped, or regulated by a movable part that opens, shuts, or partially obstructs one or more ports or passageways also : the movable part of such a device b : a device in a brass instrument for quickly channeling air flow through an added length of tube in order to change the fundamental tone by some definite interval c chiefly British : ELECTRON TUBE
4 [New Latin valva, from L] : one of the distinct usually hinged and movable pieces of which the shell of some shell-bearing animals (as lamellibranch mollusks, brachiopods, and barnacles) consists
5 [New Latin valva, from L] a : one of the segments or pieces into which a dehiscing capsule or legume separates b : the portion of various anthers (as of the barberry) resembling a lid c : one of the two encasing membranes of a diatom
– valved \ ' valvd \ adjective
– valve · less \ ' valv-l ə s \ adjective