(1):

(v. t.) To insnare; to trap; to trapan.

(2):

(n.) A snare; a trapan.

(3):

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

(4):

(n.) A kind of broad chisel for sinking shafts.

(5):

(n.) a deceiver; a cheat.

(6):

(v. t. & i.) 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.