noun (n)

• (civil law) a law established by following earlier judicial decisions(noun.communication)

  Synonym:
  case law, precedent
  

  source: wordnet30
• a system of jurisprudence based on judicial precedents rather than statutory laws(noun.group)

  Example:
  Common law originated in the unwritten laws of England and was later applied in the United States.
  

  source: wordnet30