warranty

noun pl. warranties

official authorization or sanction
justification; reasonable grounds, as for an opinion or action
Law a guarantee; specif.,
1. a guarantee or an assurance, explicit or implied, of something having to do with a contract, as of sale; esp., the seller's assurance to the purchaser that the goods or property is or shall be as represented and, if not, will be replaced or repaired
2. a guarantee by the insured that the facts are as stated in regard to an insurance risk, or that specified conditions shall be fulfilled: it constitutes a part of the contract and must be fulfilled to keep the contract in force
3. a covenant by which the seller of real estate assures, and is bound to defend, the security of the title
  in full covenant of warranty

See warranty in American Heritage Dictionary 4