1. (

• phosphorus ,
• P ,
• atomic_number_ ,

) 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 ;

2. (

• morning_star ,
• daystar ,
• Phosphorus ,
• Lucifer

) a planet (usually Venus) seen just before sunrise in the eastern sky ;