[Stormieweather]

There are also many distinct definitions of the term "Christian" (pronounced 'kristee`ân):

Most liberal Christian denominations, secularists, public opinion pollsters, and this web site [see link below] define "Christian" very broadly as any person or group who sincerely believes themselves to be Christian.

Thus, Fundamentalist and other Evangelical Protestants, Roman Catholics, Eastern Orthodox believers, Presbyterians, Methodists, Episcopalians, United Church members, Mormons, Jehovah's Witnesses, Christian Scientists, etc. are all considered Christian. They total about 75% of the North American adult population.

However, many Fundamentalist and other Evangelical Protestants define "Christian" more narrowly to include only those persons with beliefs like their own. Or they might accept as a "Christian" anyone who has been "born again" regardless of their denomination. They might estimate that about 35% of the North American adult population are real Christians.

Other denominations regard their own members to be the only Christians in the world. Some are quite small, numbering only a few thousand followers.

Different definitions on such a fundamental topic makes dialog and debate among Christian groups very difficult. It also makes estimating the number of Christians in the U.S. quite impossible. By some definitions, 75% of Americans are Christians; by other definitions, it is a small fraction of 1%.

From http://www.religioustolerance.org/chr_defn.htm