[{"Bold_text": "noun", "List Items": ["any device for halting or controlling the flow of a liquid, gas, or other material through a passage, pipe, inlet, outlet, etc.", "a hinged lid or other movable part that closes or modifies the passage in such a device.", "Anatomy.a membranous fold or other structure that controls the flow of a fluid, as one that permits blood to flow in one direction only.", "(in musical wind instruments of the trumpet class) a device for changing the length of the air column to alter the pitch of a tone.", "Zoology.one of the two or more separable pieces composing certain shells.either half of the silicified shell of a diatom.", "one of the two or more separable pieces composing certain shells.", "either half of the silicified shell of a diatom.", "Botany.one of the segments into which a capsule dehisces.a flap or lidlike part of certain anthers.", "one of the segments into which a capsule dehisces.", "a flap or lidlike part of certain anthers.", "Electronics (chiefly British). vacuum tube(def1) vacuum tube(def1).", "Archaic.one of the leaves of a double or folding door."]}, {"Bold_text": "verb (used with object)", "List Items": ["to provide with a means of controlling the flow of liquid, gas, etc., by inserting a valve."]}]