It's short for "endorsements".
"In most situations, drivers license endorsements are used for granting you additional driving privileges without having you to apply for a different type of drivers license. Most of the Pennsylvania driver's license endorsements apply to commercial drivers licenses and thus won't be useful to those who currently hold a regular class C license. However, there are exceptions to this trend, such as a motorcycle endorsement. A motorcycle endorsement can be added to any regular drivers license. "
http://www.education4drivers.com/pennsylvania/drivers-licens...It's worth noting that, in Britain, an endorsement on your licence means penalty points. So, this is an example of where EN-US and EN-GB give the same word, in the same context, a totally different meaning.