noun: Initialism of human papillomavirus. [Any of a large number of virus species in the family Papillomaviridae that affect humans, sometimes causing cervical or other cancer; it is sometimes classified as a sexually transmitted disease.]
noun: Initialism of hypoxic pulmonary vasoconstriction.
noun: Initialism of human-powered vehicle.
noun: (uncountable) Abbreviation of hydrogen peroxide vapor.
