Source : Webster's Revised Unabridged Dictionary (1913)

Digger \Dig"ger\, n.
   One who, or that which, digs.

   {Digger wasp} (Zo["o]l.), any one of the fossorial
      Hymenoptera.

Diggers \Dig"gers\, n. pl.; sing. {Digger}. (Ethnol.)
   A degraded tribe of California Indians; -- so called from
   their practice of digging roots for food.

Source : WordNet®

digger
     n 1: a laborer who digs
     2: a machine for excavating [syn: {power shovel}, {excavator},
        {shovel}]