1. A compound, such as sodium peroxide, Na2O2, that contains a peroxyl group and yields hydrogen peroxide when treated with an acid.
2. hydrogen peroxide.
3. to treat with peroxide.
4. to bleach (hair) with hydrogen peroxide.

1. a divalent radical or anion containing two oxygen atoms linked by a covalent bond; any substance containing this group which yields hydrogen peroxide when treated with an acid
2. hydrogen peroxide, especially an aqueous solution
3. to treat (something) with hydrogen peroxide, especially hair in order to bleach it

1. an oxide containing more oxygen than some other oxide of the same element. formerly peroxides were regarded as the highest oxides. cf. per-, 2.

1. 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
2. bleach with peroxide
3. an inorganic compound containing the divalent ion -O-O-