noun a rare metallic element, found in certain zinc ores. it is white, hard, and malleable, resembling aluminium, and remarcable for its low melting point (86/ f., 30/c). symbol ga. atomic weight 69.9.
2. gallium ·add. ·noun a rare metallic element, found combined in certain zinc ores. it is white, hard, and malleable, resembling aluminium, and remarkable for its low melting point (86° f., 30° c.). symbol, ga; at. wt., 69.9. gallium is chiefly trivalent, resembling aluminium and indium. it was predicted with most of its properties, under the name eka-aluminium, by mendelyeev on the basis of the periodic law. this prediction was verified in its discovery (in 1875) by its characteristic spectrum (two violet lines).