Source : Webster's Revised Unabridged Dictionary (1913)

Bevel gear \Bev"el gear`\ (Mech.)
   A kind of gear in which the two wheels working together lie
   in different planes, and have their teeth cut at right angles
   to the surfaces of two cones whose apices coincide with the
   point where the axes of the wheels would meet.

Source : WordNet®

bevel gear
     n : gears that mesh at an angle [syn: {pinion and crown wheel},
         {pinion and ring gear}]