Legal Definitions - ultimatum

An ultimatum is a final and non-negotiable proposal made in a treaty, contract, or other negotiation. It is usually given when one party wants to make it clear that if their proposal is rejected, negotiations will end or there will be serious consequences.

For example, a country might give an ultimatum to another country, saying that if they do not stop a certain action, they will declare war. Or, in a business negotiation, one company might give an ultimatum to another company, saying that if they do not agree to certain terms, they will end the negotiations and look for another partner.

Ultimatums are serious and can have significant consequences, so they are not given lightly. They are often used as a last resort when negotiations have reached a stalemate and one party feels that they need to take a strong stance to achieve their goals.