The Collaborative International Dictionary of English v.0.48:

Redan \Re*dan"\ (r?*d?n"), n. [F., for OF. redent a double
   notching or jagging, as in the teeth of a saw, fr. L. pref.
   re- re- + dens, dentis, a tooth. Cf. Redented.] [Written
   sometimes redent and redens.]
   1. (Fort.) A work having two parapets whose faces unite so as
      to form a salient angle toward the enemy.
      [1913 Webster]

   2. A step or vertical offset in a wall on uneven ground, to
      keep the parts level.
      [1913 Webster]

U.S. Gazetteer Places (2000):

Redan, GA -- U.S. Census Designated Place in Georgia
   Population (2000):    33841
   Housing Units (2000): 12106
   Land area (2000):     9.554174 sq. miles (24.745197 sq. km)
   Water area (2000):    0.049571 sq. miles (0.128388 sq. km)
   Total area (2000):    9.603745 sq. miles (24.873585 sq. km)
   FIPS code:            63952
   Located within:       Georgia (GA), FIPS 13
   Location:             33.739256 N, 84.165781 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Redan, GA
    Redan