An ultimatum is a final demand or statement that indicates the intention to take a particular action if the demands are not met. It's typically used in situations where one party feels they have been wronged and gives another party a deadline to make things right, otherwise they will take drastic measures such as breaking off relations or pursuing legal action. Ultimatums can also be given by powerful countries or organizations to weaker ones, demanding that certain conditions are met in order for diplomatic ties or aid to continue.