Which term describes a situation in which a contract is made invalid due to unforeseen circumstances?

The term that describes a situation in which a contract is rendered invalid due to unforeseen circumstances is known as frustration. In legal contexts, frustration occurs when an unforeseen event fundamentally changes the nature of a contractual obligation, making it impossible to fulfill the contract or drastically different from what was initially agreed upon. This can occur due to events such as natural disasters, changes in law, or other significant occurrences that were not anticipated by the parties at the time the contract was formed.

Rescission generally refers to the act of canceling a contract, often due to issues like misrepresentation, fraud, or mutual agreement between the parties rather than the unforeseen circumstances that lead to frustration. Termination typically involves ending a contract by one party exercising a right within the terms of the agreement, without the same implications of unforeseen circumstances. Nullification, while similar in meaning, often pertains to the action of making something legally void ab initio, but does not carry the same connotation of changing circumstances that frustration does. Therefore, frustration is the most appropriate and precise term in this scenario.