Meaning

noun a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it

noun device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone

noun control consisting of a mechanical device for controlling the flow of a fluid

originFrom Middle English valve, from Latin valva (“double door, valve”). Doublet of valva.

Etymology from Wiktionary, CC BY-SA 3.0