The Collaborative International Dictionary
Orthosilicic
Orthosilicic \Or`tho*si*lic"ic\, a. [Ortho- + silicic.] (Chem.) Designating the form of silicic acid having the normal or highest number of hydroxyl groups.
Wiktionary
orthosilicic
a. (context chemistry English) Of, relating to or derived from orthosilicic acid.