Endorsement test, a U.S. Supreme Court test for Church-State separation
Endorsement (advertising), or testimonal, written or spoken statement extolling the virtue of some product, typically a contract to promote a product by a celebrity or athlete.
A signature on a negotiable instrument indicating a person's intent to become a party to the instrument.
A specific example of the above, the signature on the back of a check, authorizing it to be deposited by a holder in due course.
Java programming language, where ""endorsed"" is a sub-directory in a lib directory, in which the contained classes are treated differently from classes in regular classpath.