Definition of CYCLOPS. 1. plural cy·clo·pes \sī-ˈklō-(ˌ)pēz\ capitalized: any of a race of giants in Greek mythology with a single eye in the middle of the forehead.2. plural cyclops [New Latin, genus name, from Latin] : any of a genus (Cyclops) of freshwater predatory copepods having a single median eye.See cyclops defined for kids.. plural cy·clo·pes \sī-ˈklō-(ˌ)pēz\ capitalized: any of a race of giants in Greek mythology with a single eye in the middle of the forehead. 2. plural cyclops [New Latin, genus name, from Latin] : any of a genus (Cyclops) of freshwater predatory copepods having a single median eye.