1. the act of endorsing; approval or support given to a person, product, or idea
Usage: formal or legal context; less common than 'endorsement'
2. a signature or written statement on the back of a document, check, or similar item
Usage: legal or financial context; archaic or formal usage

Examples

• The celebrity's endorsation of the charity helped raise awareness and donations.
• The senator's endorsation was crucial to the candidate's campaign.
• The endorsation on the back of the check made it valid for deposit.
• Her endorsation of the new policy surprised many of her colleagues.
• The company sought endorsation from industry experts to build consumer trust.
• The endorsation of the treaty required signatures from all participating nations.