quantum field theoryEnglishOxford New American Dictionaryquantum field theory /ˈkwän(t)əm fēld ˈTHiərē, , ˈkwɑn(t)əm fild ˈθɪəri, ˈTHirē, ˈθɪri/ ▸ noun Physics a field theory that incorporates quantum mechanics and the principles of the theory of relativity.