PHOSPHORUS
- the chemical element with atomic number 15 [n PHOSPHORI, PHOSPHORUSES]
- The chemical element of atomic number 15, a poisonous, combustible nonmetal that exists in two common allotropic forms, white phosphorus, a yellowish waxy solid that ignites spontaneously in air and glows in the dark, and red phosphorus, a less reactive form used in making matches
- a chemical element [n PHOSPHORUSES or PHOSPHORI]