(chemistry) a chemical element (symbol P) with an atomic number of 15, that exists in several allotropic forms. / (obsolete) any substance exhibiting phosphorescence; a phosphor

A name sometimes used for Hesperus, the personification in Greek mythology of the planet Venus.

Synonym of white phosphorus

(inorganic chemistry) A form of phosphorus that can be produced by day-long annealing of red phosphorus above 550 °C.

(chemistry) The least reactive of the allotropes of phosphorus; it has no significant commercial use.

(inorganic chemistry) the compound, P₂O₅, formed by the spontaneous combustion of white phosphorus in air; it reacts violently with water to form phosphoric acid and is used as a powerful desiccating agent

(chemistry) The most common allotrope of phosphorus; a yellow-white waxy solid that is insoluble in water and spontaneously combusts on exposure to air to form clouds of phosphorus pentoxide; used as a military smokescreen and as an incendiary weapon.

(chemistry) A stable allotrope of phosphorus; used in the manufacture of safety matches, pesticides etc.

(inorganic chemistry) A purple crystalline allotrope of phosphorus.

(chemistry, obsolete) tetraphosphorus trisulphide