What does "fluosilicic" mean?

Fluosilicic: Composed of, or derived from, silicon and fluorine. Fluosilicic acid, a double fluoride of hydrogen and silicon, H2F6Si, obtained in solution in water as a sour fuming liquid, and regarded as the type of the fluosilicates; -- called also silicofluoric acid, and hydrofluosilicic acid.