acesulfamePronunciation: /ˌasɪˈsʌlfeɪm/Definition of acesulfame noun [mass noun] a white crystalline compound used as a low-calorie artificial sweetener, typically in the form of a potassium salt ( acesulfame-K). A sulphur-containing heterocyclic compound; chemical formula: C4H5NO4S Origin: 1980s: of unknown origin