The definition of an ultimatum is a demand which, if not met, will end a relationship or otherwise result in some serious consequence.
When a woman says to her boyfriend "marry me or I am leaving you," this is an example of an ultimatum.
pl. -·tums or -·ta
a final offer or demand, esp. by one of the parties engaged in negotiations, the rejection of which usually leads to a break in relations and unilateral action, the use of force, etc. by the party issuing the ultimatum
Origin of ultimatumModern Latin ; from LL, neuter of ultimatus: see ultimate
nounpl. ul·ti·ma·tums or ul·ti·ma·ta
A final offer or demand made by one party to another, especially in diplomatic negotiations, expressing or implying the threat of serious consequences or the breakoff of relations if the terms are not accepted.
Origin of ultimatumNew Latin, from neuter of Latin ultimatus, last; see ultimate.
(plural ultimatums or ultimata)
ultimatum - Legal Definition
The final offer in negotiating an agreement, carrying with it the implication that if it is not accepted, bargaining will cease.