noun (n)

• a deliberate act of omission(noun.cognition)

  Example:
  With the exception of the children, everyone was told the news.
  

  Synonym:
  elision, exclusion
  

  source: wordnet30
• an instance that does not conform to a rule or generalization(noun.cognition)

  Example:
  All her children were brilliant; the only exception was her last child.
  An exception tests the rule.
  

  source: wordnet30
• grounds for adverse criticism(noun.communication)

  Example:
  His authority is beyond exception.
  

  source: wordnet30
• The act of excepting or excluding; exclusion; restriction by taking out something which would otherwise be included, as in a class, statement, rule.(noun)

  source: webster1913