noun (n)

• a prayer to God on behalf of another person(noun.communication)

  source: wordnet30
• the act of intervening (as to mediate a dispute, etc.)(noun.act)

  Synonym:
  intervention
  

  source: wordnet30
• The act of interceding; mediation; interposition between parties at variance, with a view to reconcilation; prayer, petition, or entreaty in favor of, or (less often) against, another or others.(noun)

  source: webster1913