Source : Webster's Revised Unabridged Dictionary (1913)

Asphyxiation \As*phyx`i*a"tion\, n.
   The act of causing asphyxia; a state of asphyxia.

Source : WordNet®

asphyxiation
     n 1: the condition of being derprived of oxygen (as by having
          breathing stopped) [syn: {suffocation}]
     2: killing by depriving of oxygen [syn: {suffocation}]