Set the world on fire Definition 1 of 3Pro Tip 1/3Fame and Impact Refers to achieving something impactful enough to become famous or widely recognized. Her innovative app quickly set the world on fire. Pro Tip 2/3Not Literal The phrase is metaphorical; it doesn't mean actually igniting anything. With his cooking skills, he's going to set the world on fire. Pro Tip 3/3Positive Connotation Often implies admiration or positive recognition for the achievement or action. Her speech at the conference truly set the world on fire.