siloxane
noun
si·lox·ane sə-ˈläk-ˌsān 
sī-
: any of various compounds containing alternate silicon and oxygen atoms in either a linear or cyclic arrangement usually with one or two organic groups attached to each silicon atom
Example Sentences
Recent Examples on the Web The researchers noticed that siloxane levels were highest during the morning rush hour, most likely because that’s when people first left their homes after applying personal-care products in the morning. 
Amanda Macmillan, Health.com, 2 May 2018 What was surprising, though, was that levels of another compound—called D5 siloxane—were just as high. Amanda Macmillan, Health.com, 2 May 2018 The chemicals are siloxanes — their basic form is one atom of oxygen linked to two atoms of silicon — which form polymers, long chains of repeating units. Gina Kolata, New York Times, 9 May 2016
Amanda Macmillan, Health.com, 2 May 2018 What was surprising, though, was that levels of another compound—called D5 siloxane—were just as high. Amanda Macmillan, Health.com, 2 May 2018 The chemicals are siloxanes — their basic form is one atom of oxygen linked to two atoms of silicon — which form polymers, long chains of repeating units. Gina Kolata, New York Times, 9 May 2016 Word History
Etymology
silicon + oxygen + methane
First Known Use
1917, in the meaning defined above