ETYM Latin, the morning star, Greek, light bringer; phos light + pherein to bring.
Highly reactive, nonmetallic element, symbol P, atomic number 15, atomic weight 30.9738. It occurs in nature as phosphates (commonly in the form of the mineral apatite), and is essential to plant and animal life. Compounds of phosphorus are used in fertilizers, various organic chemicals, for matches and fireworks, and in glass and steel.
Phosphorus was first identified 1674 by German alchemist Hennig Brand (c. 1630–?), who prepared it from urine. The element has three allotropic forms: a black powder; a white-yellow, waxy solid that ignites spontaneously in air to form the poisonous gas phosphorus pentoxide; and a red-brown powder that neither ignites spontaneously nor is poisonous.
A multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in living cells; is highly reactive and occurs in several allotropic forms; SYN. atomic number 15.