Source : Webster's Revised Unabridged Dictionary (1913)

Afterwards \Aft"er*wards\, Afterward \Aft"er*ward\, adv. [AS.
   [ae]fteweard, a., behind. See {Aft}, and {-ward} (suffix).
   The final s in afterwards is adverbial, orig. a genitive
   ending.]
   At a later or succeeding time.

Source : WordNet®

afterwards
     adv : happening at a time subsequent to a reference time; "he
           apologized subsequently"; "he's going to the store but
           he'll be back here later"; "it didn't happen until
           afterward"; "two hours after that" [syn: {subsequently},
            {later}, {afterward}, {after}, {later on}]