big bang /ˌbɪɡˈbæŋ/ noun2 •a physical theory that describes how the universe expanded from an infinitely small, hot, and dense point.Many-worlds interpretations of physics suggest that millions of big bangs might be happening as we speak. •A large implementation of a system rather than phased or gradual delivery.They're planning for an upcoming release that promises to be a big bang. formsbig bangs