- a lever over the hinge on the lid of a tankard, pressed by the thumb to raise the lid.
Origin of thumbpiece
Also called billet.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for thumbpiece
A thumbpiece must be sewn on the bag at the hasp to open it by.
He knows it will squirt if he touches the thumbpiece, but it is as liable to hit him in the face, or wet his feet as anything.Peck's Uncle Ike and The Red Headed Boy
George W. Peck
Above the handle, and attached to the lid, a metal flange or thumbpiece.
Grasp the handle, press your thumb on the thumbpiece—and presto, the lid heaves up.
They were almost upon him when Kalvar Dard pressed in the thumbpiece of the bomb; they were clutching at him when he released it.Genesis
H. Beam Piper