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

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

3. (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.

4. (n.) A snare; a trapan.

5. (n.) a deceiver; a cheat.

6. (v. t.) To ensnare; to trap; to trapan.

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