trun·nel /ˈtrʌnḷ/
  Tree·nail n.  Shipbuilding A long wooden pin used in fastening the planks of a vessel to the timbers or to each other. [Written also trenail, and trunnel.]
  ◄ ►
  Trun·nel, n. Shipbuilding See Treenail.
  ◄ ►
  trunnel
       n : a wooden peg that is used to fasten timbers in shipbuilding;
           water causes the peg to swell and hold the timbers fast
           [syn: treenail, trenail]