I think there exist more than 4 ! :thinking: (If we include past-tense, plural etc..) The most appropriate 4 according to me are : (1) CENTENARY (2) CONTENDER (3) COUNTENANCE (4) CONCATENATION :hurray: :hurray: :hurray: Other possibilities are : (1) CATENAE / CATENAS (2) CONTENDED (3) CONTENTED (4) CONCATENATING (5) CO-ATTENDING