Home › Words › T › trioxymethylenetrioxymethylenetrioxymethylene means 1,3,5-trioxane, a stable cyclic trimer of formaldehyde.EtymologyFrom tri- + oxy- + methylene.noun1,3,5-trioxane, a stable cyclic trimer of formaldehyde.Definitions & examples from Wiktionary (CC BY-SA 3.0).