gallium: Meaning and Definition of

gal•li•um

1. a rare, steel-gray, trivalent metallic element used in high-temperature thermometers because of its high boiling point (1983°C) and low melting point (30°C). Symbol: Ga; at. wt.: 69.72; at. no.: 31; sp. gr.: 5.91 at 20°C.