Source : Webster's Revised Unabridged Dictionary (1913)

Thenceforth \Thence`forth"\, adv.
   From that time; thereafter.

         If the salt have lost his savor, wherewith shall it be
         salted? it is thenceforth good for nothing. --Matt. v.
                                                  13.

   Note: This word is sometimes preceded by from, -- a
         redundancy sanctioned by custom. --Chaucer. --John.
         xix. 12.

Source : WordNet®

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