phosphorus

(noun) a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms. Synonyms: P, atomic number 15.

(noun) a planet (usually Venus) seen just before sunrise in the eastern sky. Synonyms: morning star, daystar, Phosphorus, Lucifer.