According to the Internet, a "maid of honour" in the UK historically meant that you were the attendant of a queen. Although monarchy may be limited in the political world, things haven't really changed for wedding days and ceremonies! If the title of "maid of honor" (MOH) is bestowed upon you, gear up to serve your queen (aka the bride!) in all the days leading up to, the day of, and even after the wedding.
Photo Source VisualMasterpiece
There is no history book or set-in-stone precedent that clearly states what a MOH's duties are. And although there's no definite answer, there are some things that should be on every MOH's checklist.