The story
From hexamethyl + cyclo- + trisiloxane.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A cyclic organosilicon compound consisting of a six-membered ring containing alternating silicon and oxygen atoms, with each silicon atom bonded to two methyl groups; used as an intermediate in silicone polymer production. Full definition →
From hexamethyl + cyclo- + trisiloxane.
Etymology from Wiktionary, CC BY-SA 4.0.