how christians define the christians group that is in the right path? Can you please explain. And which is the majority group?
Like with pretty much everyone else, how Christians define who is and who is not on the right path is by claiming that they are and that those who disagree with them are not. There are of course groups that allow for quite a bit of latitude before declaring a person is wrong and other groups that allow for so little differnece of opinion that they think that they have heaven all to themselves.
So it is that you have groups of denominations like the Baptists, Presbyterians, Methodists, Lutherans, Nazarenes, Assemblies of God, Apostolic Church, Disciples of Christ, Episcopalians, Reformed Churches, Salvation Army, Pentecostals, Four Square Gospel, Mennonites, Church of the Brethren, Congregationalists, Moravians, Pilgrim Holiness, Wesleyans, United Church of Christ, Church of God, Quakers, Amish, and Anglicans that pretty much see each other as all equally a part of the body of Christ even if they don't see eye to eye on all of the details of theology or practice.
Then you have the groups like the Catholics, Orthodox, and Coptics that recognize that these other groups are composed of genuine believers and followers of Jesus Christ, but they don't recognize the institutions in which they gather as being legitimate churches unless they can trace their roots by direct laying on of hands in the ordination of their clergy back to the apostles, which is something they pretty much reserve for themselves. They declare what most people would call churches to be ecclesiatical communities. (BTW, I think this if funny because ecclesiatiacal is just a fancy word meaning "church".)
And then you have groups such as the Mormons, Jehovahs' Witness, the Way International, the Moonies, and others who each think that they are the one and only group that is truly Christian and that everyone else is apostate, even if their ideas have next to nothing in common with what has been the historic teaching of Christianity for the last 2000 years.
In terms of numbers, Wikipedia provides the following membership information:
Catholicism (Roman Catholic, Old Catholic, etc) - 1116 million
Anglicans - 73 million
Eastern Orthodoxy (Greek Orthodox, Russian Orthodox, Karamanli Turkish Church, etc.) - 225 million
Oriental Orthodox (Coptic, Ethopian Orthodox, Syriac Orthodox, Armenian Apostolic Church) - 72 million
Historic Protestantism (Baptist, Lutheran, Methodist, Presbyterian, Quaker, etc.) - 340 million
Pentecostal Protestanism (Assemblies of God, Apostolic Church, Church of God, etc.) - 105 million
Non-trinitarian (Unitarians, Jehovah's Witnesses, Christadelphians, etc.) - 10 million
For myself, except for those that are non-trinitarian (e.g. Unitarians and JWs) or that teach the one can earn one's salvation through good works (e.g. Mormons), I would include all in the above list as Christian.
