phosphorus pentoxide: Meaning and Definition of

phos'phorus pent•ox'ide

1. a white, deliquescent, crystalline powder, PO, that, depending upon the amount of water it absorbs, forms orthophosphoric acid, metaphosphoric acid, or pyrophosphoric acid, produced by the burning of phosphorus in dry air: used in the preparation of phosphoric acids, as a drying and dehydrating agent, and in organic synthesis. Also called