Any of a large group of semi-inorganic polymers based on siloxanes. Silicones were first discovered by F. Kipping in England in 1900, but were not commercially produced until 1943 by Dow Corning. Silicones can be liquids, gels, solids and elastomers. In general, they have excellent heat and chemical resistance and are water repellent. Silicones are used as adhesives, protective coatings and paints. Synonyms: polysiloxane; organosiloxane. Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]