Trepan

Part of speech: noun (n.)

1. A crown-saw or cylindrical saw for perforating the skull, turned, when used, like a bit or gimlet. See Trephine.

2. A kind of broad chisel for sinking shafts.

Part of speech: noun (n.)

1. A snare; a trapan. Snares and trepans that common life lays in its way. South.

2. a deceiver; a cheat. He had been from the beginning a spy and a trepan. Macaulay.

Part of speech: verb (v.)

To perforate (the skull) with a trepan, so as to remove a portion of the bone, and thus relieve the brain from pressure or irritation; to perform an operation with the trepan.

Part of speech: verb (v.)

To insnare; to trap; to trapan. Guards even of a dozen men were silently trepanned from their stations. De Quincey.