Definition of "Peroxide" :

noun: a viscous liquid with strong oxidizing properties; a powerful bleaching agent; also used (in aqueous solutions) as a mild disinfectant and (in strong concentrations) as an oxidant in rocket fuels

noun: an inorganic compound containing the divalent ion -O-O-

verb: bleach with peroxide

"She must peroxide her hair-it looks unnaturally blond."