Source : Webster's Revised Unabridged Dictionary (1913)

Reenter \Re*["e]n"ter\ (r?*?n"t?r), v. t.
   1. To enter again.

   2. (Engraving) To cut deeper, as engraved lines on a plate of
      metal, when the engraving has not been deep enough, or the
      plate has become worn in printing.

Reenter \Re*["e]n"ter\, v. i.
   To enter anew or again.

   {Re["e]ntering angle}, an angle of a polygon pointing inward,
      as a, in the cut.

   {Re["e]ntering polygon}, a polygon having one or more
      re["e]ntering angles.