The Collaborative International Dictionary of English v.0.48:

Thereafter \There*af"ter\, adv. [AS. [eth][=ae]r[ae]fter after
   that. See There, and After.]
   1. After that; afterward.
      [1913 Webster]

   2. According to that; accordingly.
      [1913 Webster]

            I deny not but that it is of greatest concernment in
            the church and commonwealth to have a vigilant eye
            how books demean themselves as well as men; and
            thereafter to confine, imprison, and do sharpest
            justice on them as malefactors.       --Milton.
      [1913 Webster]

   3. Of that sort. [Obs.] "My audience is not thereafter."
      --Latimer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

thereafter
    adv 1: from that time on; "thereafter he never called again"
           [syn: thereafter, thenceforth]