Home › Words › M › microfillmicrofillmicrofill · noun — A spreadable microparticulate substance used in dental work.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom micro- + fill.nounA spreadable microparticulate substance used in dental work.verbTo fill with this substance.Definitions & examples from Wiktionary (CC BY-SA 3.0).