The term that describes a duty that is enforced by a court and where non-fulfilment may incur a penalty.

Sometimes known as a repudiatory breach, is a breach of an essential part of a contract that it permits the distressed party to terminate performance of the contract, in addition to entitling that party to sue for damages.

A breach of contract that is so fundamental that it permits the injured party to terminate the performance of the contract, in addition to entitling that party to sue for damages.

Significant enough substantial failure in the performance of a contract, as to give the affected party the right to sue for damages as well as release the aggrieved party from its obligations.

Any matter of fact that a party to a claim or action offers to provide to prove or disprove an issue in the case. The strongest type of evidence is that which provides direct proof of the truth of an assertion. At the other extreme is evidence that is merely consistent with an assertion but does not rule out other, contradictory assertions, and may be viewed as circumstantial evidence.