peroxide

1. (inorganic chemistry) A divalent radical or anion containing two oxygen atoms linked by a covalent bond; any substance containing this group yields hydrogen peroxide when treated with an acid.countableuncountable

2. (organic chemistry) Any compound containing the functional group R-O-O-R'.Examples: "Thus far, Dr. Petrakis said, he had found that in women with […] extractable breast fluid, the amount of lipid peroxides in the fluid was on the average seven times higher in Caucasian women than in women of Chinese de[s]cent. In addition, women with cystic breast disease, who face a higher than usual risk of breast cancer, appear to have more peroxides in their breast fluid than women with normal breasts."; "The O–O bond in benzoyl peroxide and the C–N bonds in AIBN homolyze under thermal or photochemical conditions."countableuncountable