Monarchy
A constitutional monarchy is a form of government that is usually a democracy and has a constitution, with the monarch as head of state.  Either the monarch has to obey the laws like everyone else, or there are special laws that say what the monarch can and cannot do.  The monarch usually can not decide their special laws on their own.  There may be laws about whom the monarch's children can marry, for example, that are passed by the Parliament.  For example, in the Netherlands, if a member of the royal family marries without the permission of Parliament, they cannot become king or queen themselves.  The army and navy may swear an oath to the monarch, but the real control is given to the elected government.  There are laws about property and the order of succession (who gets to be the next monarch) that can only be changed by the elected government.  Usually the monarch must sign laws into effect, but is required to follow the will of the elected government.