(inorganic chemistry) A yellow oxide of lead, PbO, used in the manufacture of paints and glass.

A crescent-shaped lake formed near a flat-valleyed river when one of its meanders becomes pinched off and isolated.

(inorganic chemistry) The simple systematic name for water, H₂O.

A nightclub or similar venue in which patrons pay to inhale doses of gas containing concentrations of oxygen higher than in air.

Therapeutic administration of oxygen.

(chemistry) Any of a class of organic compound formed by addition of an oxygen atom to an amine - R₃N⁺-O⁻, but sometimes written R₃N=O.

A plastic or rubber mask through which oxygen may be breathed from a storage tank.

(chemistry) An aminoxyl radical.

(organic chemistry) An arene epoxide.

(inorganic chemistry, organic chemistry) The derivative of arsine H₃As=O, or its organic derivatives.