The Oxford Thesaurus An A-Z Dictionary of Synonyms - endorsementn.

1) indorsement, approval, affirmation, sanction, authorization, confirmation, ratification, support, backing, approbation, seal or stamp of approval, imprimatur, Colloq OK, okay: He is acting with the full endorsement of his union. 2) counter-signature: His endorsement is on the back of the cheque.