noun (n)

• a stipulated condition(noun.communication)

  Synonym:
  provision
  

  source: wordnet30
• An article or clause in any statute, agreement, contract, grant, or other writing, by which a condition is introduced, usually beginning with the word provided; a conditional stipulation that affects an agreement, contract, law, grant, or the like; as, the contract was impaired by its proviso.(noun)

  source: webster1913