What does "metasilicic" mean?

Metasilicic: Designating an acid derived from silicic acid by the removal of water; of or pertaining to such an acid. Note: The salts of metasilicic acid are often called bisilicates, in mineralogy, as Wollastonite (CaSiO3). Metasilicic acid (Chem.), a gelatinous substance, or white amorphous powder, analogous to carbonic acid, and forming many stable salts.