Jigger \Jig"ger\ (j[i^]g"g[~e]r), n. [A corrupt. of chigre.]
   1. (Zool.) A species of flea ({Tunga penetrans}, or
      {Sarcopsylla penetrans}, or {Pulex penetrans}), which
      burrows beneath the skin; called also {jigger flea}. See
      {Chigoe}.
      
[1913 Webster]


   2. (Zool.) Any one of several species of small red mites
      (esp. {Tetranychus irritans} and {Tetranychus Americanus})
      of the family {Trombiculidae}, which, in the larval or
      leptus stage, burrow beneath the skin of man and various
      animals, causing great annoyance. Also called {chigger}.
      [Southern U. S.]
      [Webster 1913 Suppl. +PJC]