- a rare-earth, metallic, trivalent element, named from its green salts. Symbol: Pr; atomic weight: 140.91; atomic number: 59; specific gravity: 6.77 at 20°C.
- a malleable ductile silvery-white element of the lanthanide series of metals. It occurs principally in monazite and bastnaesite and is used with other rare earths in carbon-arc lights and as a pigment in glass. Symbol: Pr; atomic no: 59; atomic wt: 140.90765; valency: 3; relative density: 6.773; melting pt: 931°C; boiling pt: 3520°C
