/plat"n euhm, plat"neuhm/ , n.
1. Chem. a heavy, grayish-white, highly malleable and ductile metallic element, resistant to most chemicals, practically unoxidizable except in the presence of bases, and fusible only at extremely high temperatures: used for making chemical and scientific apparatus, as a catalyst in the oxidation of ammonia to nitric acid, and in jewelry. Symbol: Pt; at. wt.: 195.09; at. no.: 78; sp. gr.: 21.5 at 20°C.
2. a light, metallic gray with very slight bluish tinge when compared with silver.
adj.
3. made of platinum.
4. (of a record, CD, or cassette) having sold a minimum of one million copies.
[ 1805-15; platina ]