/ ˌʌltɪˈmeɪtəm; NAmE / noun
( pl. ul·ti·matums or ul·ti·ma·ta ) a final warning to a person or country that if they do not do what you ask, you will use force or take action against them :
to issue an ultimatum
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WORD ORIGIN
mid 18th cent.: from Latin , neuter past participle of ultimare come to an end.