Silicone

noun, Chemistry.
1.
any of a number of polymers containing alternate silicon and oxygen atoms, as (–Si–O–Si–O–) n, whose properties are determined by the organic groups attached to the silicon atoms, and that are fluid, resinous, rubbery, extremely stable in high temperatures, and water-repellent: used as adhesives, lubricants, and hydraulic oils and in electrical insulation, cosmetics, etc.
noun
1.
(chem)

any of a large class of polymeric synthetic materials that usually have resistance to temperature, water, and chemicals, and good insulating and lubricating properties, making them suitable for wide use as oils, water-repellents, resins, etc. Chemically they have alternate silicon and oxygen atoms with the silicon atoms bound to organic groups
(as modifier): silicone rubber

See also siloxane

silicone sil·i·cone (sĭl’ĭ-kōn’)
n.
Any of a group of silicon compounds in solid, liquid, or gel form, characterized by wide-range thermal stability, high lubricity, extreme water repellence, and physiological inertness and used in many medical products, including surgical implants and dental impression materials.
silicone
(sĭl’ĭ-kōn’)
Any of a class of chemical compounds consisting of long chains of alternating silicon and oxygen atoms, with two organic radicals, typically a methyl (CH3) and a phenyl (C6H5) group, attached to each silicon atom. Silicones are very stable and resist the effects of water, heat, and oxidizing agents. They are used to make adhesives, lubricants and synthetic rubber.