noun (n)

• a promotional statement (as found on the dust jackets of books)(noun.communication)

  Synonym:
  blurb, endorsement
  

  source: wordnet30
• a speech seconding a motion(noun.communication)

  Synonym:
  endorsement, second, secondment
  

  source: wordnet30
• formal and explicit approval(noun.communication)

  Synonym:
  countenance, endorsement, imprimatur, sanction, warrant
  

  source: wordnet30
• a signature that validates something(noun.communication)

  Synonym:
  endorsement
  

  source: wordnet30
• the act of endorsing(noun.act)

  source: wordnet30
• The act of writing on the back of a note, bill, or other written instrument.(noun)

  source: webster1913