Yes, the term ‘Christian’ is considered a proper noun. Proper nouns are specific names that identify individual people, places, or organizations. In this case, ‘Christian’ refers to a particular religion or to individuals who adhere to that religion. As a result, when ‘Christian’ is used to denote followers of Christianity, it is capitalized, signifying its status as a proper noun.
For example, when we say, ‘She is a Christian,’ we are using ‘Christian’ to specifically identify someone’s religious affiliation. Likewise, when it is part of a title or descriptor, such as ‘Christian community’ or ‘Christian doctrine,’ it maintains its proper noun status as it closely relates to defined beliefs or practices of a specific group.