A term collateral to the main purpose of the contract. A warranty is a less important promise of a contract and breach will not repudiate the contract­ - compare with a term or condition. If a party to the contract breaches a warranty the contract will not be rescinded but the innocent party may claim damages.

If the term of the contract is a warranty the innocent party may sue for damages for breach of warranty but cannot repudiate the contract  - see term, condition. Whether or not the promise is a term or warranty will depend on the intention of the parties to the contract. The remedy for a breach of warranty may be stated in the contract. 

See breach of contract