a non-metallic chemical element of the nitrogen family that occurs widely, esp as phosphates: symbol P, atomic number 15
The two main forms are white phosphorus, which is a soft waxy solid that is poisonous, phosphorescent, and highly inflammable, and red phosphorus, which is less reactive, does not phosphoresce, and is used in safety matches, There is also an even less reactive black variety, somewhat resembling graphite
a phosphorescent substance or body, esp one that shines or glows in the dark; = phosphor
phosphorous adj
[via Latin from Greek phōsphoros: see phosphor]