tre·pan /trɪˈpæn/
  環鋸,鑽孔機(vt.)用環鋸行手術,誘入圈套,欺騙
  Tre·pan n.
  1. Surg. A crown-saw or cylindrical saw for perforating the skull, turned, when used, like a bit or gimlet. See Trephine.
  2. Mining A kind of broad chisel for sinking shafts.
  Tre·pan, v. t. & i. [imp. & p. p. Trepanned p. pr. & vb. n. Trepanning.]  Surg. 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.
  Tre·pan, 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.
  Tre·pan, v. t. To insnare; to trap; to trapan.
     Guards even of a dozen men were silently trepanned from their stations.   --De Quincey.
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  trepan
       n 1: a surgical instrument used to remove sections of bone from
            the skull [syn: trephine]
       2: a drill for cutting circular holes around a center
       v : cut a hole with a trepan, as in surgery
       [also: trepanning, trepanned]