peroxide

Concise Oxford English Dictionary © 2008 Oxford University Press:
peroxide/pəˈrɒksʌɪd/

▶noun

• 1 Chemistry a compound containing two oxygen atoms bonded together in its molecule or as the anion O₂²⁻.

• 2 hydrogen peroxide, especially as used as a bleach for the hair.

▶verb bleach (hair) with peroxide.

– origin C19: from sense 2 of per- + oxide.