1. In astronomy, the ancient Greek name for the planet Venus when seen as a morning star.
2. A solid, nonmetallic element existing in one form that is yellow, poisonous, flammable, and luminous in the dark and in another form that is red, less poisonous, and less flammable.
3. Ordinarily, elemental phosphorus occurs as the white form, an exceedingly poisonous. waxy yellowish solid, transparent and colorless if pure and ignites spontaneously in air.
4. Phosphorus is used in matches, fertilizers, pesticides, and various other industrial products; and, it is an essential element of the human diet and is the main component of bones and teeth. It is involved in some form in virtually all processes of metabolism.

Information is located at Chemical Element: phosphorus .

In toxicology, ulceration, tissue death, and bone damage in the jaw of an individual who is chronically exposed to yellow (toxic) phosphorus.