The Collaborative International Dictionary of English v.0.48:

Obliteration \Ob*lit`er*a"tion\, n. [L. obliteratio: cf. F.
   oblit['e]ration.]
   The act of obliterating, or the state of being obliterated;
   extinction. --Sir. M. Hale.
   [1913 Webster]

WordNet (r) 3.0 (2006):

obliteration
    n 1: destruction by annihilating something [syn: annihilation,
         obliteration]
    2: the complete destruction of every trace of something [syn:
       eradication, obliteration]