(inorganic chemistry) 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.

Hydrogen peroxide, especially when in an aqueous solution used as a bleach.

(organic chemistry) Any compound containing the functional group R-O-O-R'.

(transitive) To treat (something) with hydrogen peroxide, especially hair in order to bleach it.