The Collaborative International Dictionary of English v.0.48:

Reenter \Re*en"ter\, Re-enter \Re-en"ter\(r?*?n"t?r), v. t.
   1. To enter again; as, You cannot re-enter the country with
      this visa.
      [1913 Webster]

   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.
      [1913 Webster]

   3. (Computers) To put (data) into a document or form on a
      computer again; -- usually to correct an erroneous entry;
      as, the password was incorrect, and had to be reentered.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Reenter \Re*en"ter\, v. i.
   To enter anew or again.
   [1913 Webster]

   Reentering angle, an angle of a polygon pointing inward, as
      a, in the cut.

   Reentering polygon, a polygon having one or more reentering
      angles.
      [1913 Webster]