Source : Webster's Revised Unabridged Dictionary (1913)

Butt joint \Butt" joint`\
   A joint in which the edges or ends of the pieces united come
   squarely together instead of overlapping. See 1st {Butt}, 8.

Source : WordNet®

butt joint
     n : a joint made by fastening ends together without overlapping
         [syn: {butt}]