a silvery, malleable chemical element, one of the rare-earth elements, whose salts are generally green in color and are used to color glasses and enamels: symbol, Pr; at. no., 59
See praseodymium in American Heritage Dictionary 4
(prāˌzē-ō-dĭmˈē-əm, prāˌsē-)
noun Symbol Pr
A soft, silvery, malleable, ductile rare-earth element that develops a characteristic green tarnish in air. It occurs naturally with other rare earths in monazite and is used to color glass and ceramics yellow, as a core material for carbon arcs, and in metallic alloys. Atomic number 59; atomic weight 140.908; melting point 935°C; boiling point 3,127°C; specific gravity 6.8; valence 3, 4. See Table at element.