A denomination, in the Christian sense of the word, is an identifiable religious body or grouping under a common name, structure, and/or doctrine drawn from the three major divisions of Churches: Roman Catholic, Eastern Orthodox, and Protestant.
The term may be applied in particular to Protestant church bodies or groupings. Notable among these are: Anglican, Methodist, Reformed and Presbyterian, Congregational, Baptist, Lutheran, Anabaptist (made up of the Amish, Hutterites, and Mennonites), Pentecostal and Charismatic, and United and Uniting churches. It is also common today for churches to classify themselves as non-denominational. The degree to which denominations differ and their acceptance within Christianity varies widely.
To speak of Denominationalism may presume that some or all Christian groups are, in some sense, versions of the same basic thing regardless of their distinguishing labels. Not all churches agree to this; for instance, the Roman Catholic and Orthodox Churches do not include themselves under this term as its implication of interchangeability does not agree with their theological teachings.
There are some groups which practically all others would view as apostate and therefore not legitimate versions of Christianity. Others may be seen as heretical, even by some churches of their own denomination. To be a heretic means only that one holds an erroneous doctrine of importance, not that one has renounced the Christian faith.