Home › Words › Q › quintillionairequintillionairequintillionaire · noun — somebody whose wealth is at least one quintillion (10¹⁸) currency units.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom quintillion + -aire.nounSomebody whose wealth is at least one quintillion (10¹⁸) currency units.Definitions & examples from Wiktionary (CC BY-SA 3.0).