The Collaborative International Dictionary
Bisilicate
Bisilicate \Bi*sil"i*cate\, n. (Min. Chem.) A salt of metasilicic acid; -- so called because the ratio of the oxygen of the silica to the oxygen of the base is as two to one. The bisilicates include many of the most common and important minerals.
Wiktionary
bisilicate
n. A salt of metasilicic acid, in which the ratio of the oxygen of the silica to the oxygen of the base is two to one.