Definition of "Endorsement" :

noun: the act of endorsing

"A star athlete can make a lot of money from endorsements."

noun: a signature that validates something

"The cashier would not cash the check without an endorsement."

noun: formal and explicit approval

"A Democrat usually gets the union's endorsement."

noun: a speech seconding a motion

noun: a promotional statement (as found on the dust jackets of books)