The Collaborative International Dictionary
Protosilicate
Protosilicate \Pro`to*sil"i*cate\, n. [Proto- + silicate.] (Chem.) A silicate formed with the lowest proportion of silicic acid, or having but one atom of silicon in the molecule.
Wiktionary
protosilicate
n. (context chemistry English) A silicate formed with the lowest proportion of silicic acid, or having only one atom of silicon in the molecule.