- ☆ platinum [plat′'n əm]n.[ModL < Sp platina, dim. of plata, silver < Prov, metal plate, silver bar, silver < VL * plattus, flat: see PLATE]a silver-colored, malleable, ductile, metallic chemical element that is highly resistant to corrosion and tarnish, used as a chemical catalyst, for acid-proof containers, ignition fuses, jewelry, dental alloys, etc.: symbol, Pt; at. no., 78: see the periodic table of elements in the Reference Supplementadj.[by assoc. with the platinum-plated copy awarded to the performer(s) ]designating a record, tape, disc, video, etc. which has registered sales of a specified number, as two million, or value, as $1,000,000: platinum reflects a greater number or value than gold
English World dictionary. V. Neufeldt. 2014.