ultimatum /ˌʌltəˈmeɪtəm/ noun plural ultimatums or ultimata /-tə/ /ˌʌltəˈmeɪtə/ plural ultimatums or ultimata /-tə/ /ˌʌltəˈmeɪtə/ Learner's definition of ULTIMATUM
[count]
: a final threat : a promise that force or punishment will be used if someone does not do what is wanted最后通牒