Home › Words › M › methidathionmethidathionmethidathion · noun — A particular organophosphate insecticide.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom me(thoxy-) + thi(a)d(i)a(zol) + -thion.nounA particular organophosphate insecticide.Definitions & examples from Wiktionary (CC BY-SA 3.0).