Source : Webster's Revised Unabridged Dictionary (1913)

Twibil \Twi"bil\, n. [AS. twibill; twi- (in comp.) two + bill,
   bil, an ax hoe, bill. See {Twice}, and {Bill} a cutting
   instrument.]
   1. A kind of mattock, or ax; esp., a tool like a pickax, but
      having, instead of the points, flat terminations, one of
      which is parallel to the handle, the other perpendicular
      to it. [Prov. Eng.]

   2. A tool for making mortises. [Obs.]

   3. A reaping hook.