- an allotropic nonmetallic element occurring in phosphates and living matter. Ordinary phosphorus is a toxic flammable phosphorescent white solid; the red form is less reactive and nontoxic: used in matches, pesticides, and alloys. The radioisotope phosphorus-32 (radiophosphorus), with a half-life of 14.3 days, is used in radiotherapy and as a tracer. Symbol: P; atomic no: 15; atomic wt: 30.973 762; valency: 3 or 5; relative density: 1.82 (white), 2.20 (red); melting pt: 44.1°C (white); boiling pt: 280°C (white)
- a less common name for a phosphor
Word Origin for phosphorus
- a morning star, esp Venus
"substance or organism that shines of itself," 1640s, from Latin phosphorus "light-bringing," also "the morning star" (a sense attested in English from 1620), from Greek Phosphoros "morning star," literally "torchbearer," from phos "light," contraction of phaos "light, daylight" (related to phainein "to show, to bring to light;" see phantasm) + phoros "bearer," from pherein "to carry" (see infer).
As the name of a non-metallic chemical element, it is recorded from 1680, originally one among several substances so called; the word used exclusively of the element from c.1750. It was discovered in 1669 by Henning Brand, merchant and alchemist of Hamburg, who derived it from urine. Lavoisier demonstrated it was an element in 1777. According to Flood, "It is the first element whose discoverer is known."
- A highly reactive poisonous nonmetallic element occurring naturally in phosphates, such as hydroxyapatite, and an essential constituent of protoplasm, nerve tissue, and bone. Its radioisotope is used to localize and treat cancers and peritoneal or pleural effusions caused by metastatic disease, to determine blood volume, to study peripheral vascular disease, and to treat blood diseases such as polycythemia vera, chronic myelocytic leukemia, and chronic lymphocytic leukemia. Atomic number 15.
- A phosphorescent substance.
- A highly reactive, poisonous nonmetallic element occurring naturally in phosphates, especially in the mineral apatite. It exists in white (or sometimes yellow), red, and black forms, and is an essential component of protoplasm. Phosphorus is used to make matches, fireworks, and fertilizers and to protect metal surfaces from corrosion. Atomic number 15; atomic weight 30.9738; melting point (white) 44.1°C; boiling point 280°C; specific gravity (white) 1.82; valence 3, 5. See Periodic Table.