Source : WordNet®

ionisation
     n 1: the condition of being dissociated into ions (as by heat or
          radiation or chemical reaction or electrical discharge);
          "the ionization of a gas" [syn: {ionization}]
     2: the process of ionizing; the formation of ions by separating
        atoms or molecules or radicals or by adding or subtracting
        electrons from atoms by strong electric fields in a gas
        [syn: {ionization}]