The Collaborative International Dictionary of English v.0.48:

Subsequently \Sub"se*quent*ly\, adv.
   At a later time; afterwards.
   [1913 Webster]

WordNet (r) 3.0 (2006):

subsequently
    adv 1: 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, afterwards, afterward, after, later on]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "subsequently":
   after, after all, after that, afterward, afterwards, behind,
   by and by, ex post facto, in the aftermath, in the sequel, infra,
   later, latterly, next, since, then, thereafter, thereon, thereupon,
   therewith