butterfly valve

noun

1. a clack valve having two flaps with a common hinge.
2. a valve, as the throttle valve in a carburetor, that swings about a central axis across its face.

butterfly valve

noun

1. a disc that acts as a valve by turning about a diameter, esp one used as the throttle valve in a carburettor
2. a non-return valve consisting of two semicircular plates hinged about a common central spindle

Word History and Origins

Origin of butterfly valve¹

First recorded in 1860–65