“+...- noun
Etymology: International Scientific Vocabulary fluo- + silicic
: an unstable corrosive poisonous acid H 2 SiF 6 that is known chiefly in aqueous solution and in the form of its salts, that is made usually by the reaction of silicon tetrafluoride with water (as in the manufacture of superphosphate), and that is used especially as a hardening and waterproofing agent for building materials and ceramic products, as a disinfectant, and in some electrochemical processes — called also hydrofluosilicic acid