How is someone termed as a Catholic ,Protestant or Orthodox Christian ?   

Roman catholic and orthodox religions started at about the same time in different parts of the holy lands. They basically follow the same beliefs except they have different leaders. All the other Christian religions are offshoots of the first 5 groups of orthodox or catholics, mainly formed because some charismatic leader decided he didn't like some of the rules set down by the original church, ior thought the church wasn't following them correctly. Basically, its because that person wanted to be the boss of his own group.

The only ones I can respond to are Catholic and Protestant. Catholics belong to the Catholic Church, run by the Vatican and headed by the Pope. Protestants are the religions that sprang up after the teaching of Martin Luther, that believed religion should be in the hands of the people instead of the church. He said that every man is a priest, and every man is responsible to God directly. Those people 'protested' against the organized and very powerful Catholic church of the time. From that Protestant movement came Lutherans, Methodists, Protestants, Baptists, etc.