Source : Webster's Revised Unabridged Dictionary (1913)

Gib \Gib\, n. [Etymol. uncertain.]
   A piece or slip of metal or wood, notched or otherwise, in a
   machine or structure, to hold other parts in place or bind
   them together, or to afford a bearing surface; -- usually
   held or adjusted by means of a wedge, key, or screw.

   {Gib and key}, or {Gib and cotter} (Steam Engine), the fixed
      wedge or gib, and the driving wedge,key, or cotter, used
      for tightening the strap which holds the brasses at the
      end of a connecting rod.