A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth. Christians believe Jesus is the Messiah (the Christ in Greek-derived terminology) prophesied in the Hebrew Bible, and the Son of God. Most Christians believe in the doctrine of the Trinity ("tri-unity"), a description of God as Father, as Son, and as Holy Spirit. This includes Roman Catholicism, Orthodox Christianity, and the vast majority of Protestantism. A minority are Nontrinitarians.
The term "Christian" is also used adjectivally to describe anything associated with Christianity, or in a proverbial sense "all that is noble, and good, and Christ-like."
The Greek word Χριστιανός (christianos)—meaning "follower of Christ"—comes from Χριστός (christos)—meaning "anointed one"—with an adjectival ending borrowed from Latin to denote adhering to, or even belonging to, as in slave ownership. In the Greek Septuagint, christos was used to translate the Hebrew מָשִׁיחַ (Mašíaḥ, messiah), meaning "[one who is] anointed." In other European languages, equivalent words to 'Christian' are likewise derived from the Greek, such as 'Chrétien' in French and 'Cristiano' in Spanish.
The first recorded use of the term (or its cognates in other languages) is in the New Testament, in Acts 11:26, which states "...in Antioch the disciples were first called Christians." The second mention of the term follows in Acts 26:28, where Herod Agrippa II replies to Paul the Apostle, "Do you think that in such a short time you can persuade me to be a Christian?" The third and final New Testament reference to the term is in 1 Peter 4:16, which exhorts believers, "...if you suffer as a Christian, do not be ashamed, but praise God that you bear that name". Mattison suggests that "[t]he New Testament's use of this term indicates that it was a term of derision, a term placed upon Christ's followers by their critics."
The earliest occurrences of the term in non-Christian literature include Josephus, referring to "the tribe of Christians, so named from him;" Pliny the Younger in correspondence with Trajan; and Tacitus, writing near the end of the first century. In the Annals he relates that "by vulgar appellation [they were] commonly called Christians" and identifies Christians as Nero's scapegoats for the Great Fire of Rome.
A wide range of beliefs and practices is found across the world among those who call themselves Christian. There is usually a consensus within a denomination about what defines a Christian, but often little agreement among members of different denominations on a common definition of "Christianity." Philosopher Michael Martin, in his book The Case Against Christianity, evaluated three historical Christian creeds to establish a set of basic assumptions which include belief in theism, the historicity of Jesus, the Incarnation, salvation through faith in Jesus, and Jesus as an ethical role model. Included in his analysis were the Apostles' Creed, the Nicene Creed, and the Athanasian Creed.
The Ontario Consultants on Religious Tolerance claim there are significant differences in the various ways people define "Christian." They suggest it is probably impossible to have any large group of adults reach a consensus on precisely who is a "Christian," and who is not. They identify these seven as common ways a Christian is popularly defined as being someone who has:
Heard the Gospel in a certain way, and accepted its message, or
Become "saved"─i.e., they have trusted Jesus as Lord and Savior), or
Been baptized as an infant, or
Gone to church regularly, or
Recited and agreed with a specific church creed or creeds, or
Believed that they understand and follow Jesus' teachings, or
Led a decent life.
– Religious Tolerance
Religious Tolerance says that the most common definition of a Christian is one who is "a follower of Christ and his teachings." After saying that, they provide the following caveat:
This sounds simple and meaningful until you realize that there is a great diversity of beliefs about what Christ actually taught. There is general agreement on what Jesus said, but little consensus on what Jesus meant. One needs only to consult the books printed by InterVarsity Press, Zondervan, and other publishers with names like "Four views on salvation ... ." They describe the full range of conservative Christian beliefs about important religious topics. In these books, a number of leading evangelical Christian writers explain their personal views on a specific topic, and critique each others beliefs as being false. Each of the authors is intelligent, sincere, serious, devout, thoughtful theologian and is quite confident that their own belief is the only one that is biblically based. Yet, the authors' conclusions conflict with each other.
The definitional challenge is further compounded by theological differences concerning biblical definitions of salvation, usually known as the faith vs works controversy. Some believe that the Book of James in particular presents a doctrine of justification based upon works─a position that contradicts Paul’s doctrine of justification based upon faith. One writer combines the two views this way: "Works of the law that are outward acts of ritual for the purpose of receiving merit are of no value for attaining salvation. However, those who trust in and obey Jesus Christ will produce works that are motivated by the Spirit that will serve to build up the Kingdom of God...."
Anderson Cooper has reported that in the United States, "more than 85 percent is Christian and two-thirds of [Americans], a number that's climbing, consider America a Christian nation. But from there, the lines start to blur."
As the identification of the Messiah with Jesus is not accepted within Judaism, the Talmudic term for Christians in Hebrew is Notzrim ("Nazarenes"), originally derived from the fact that Jesus came from the village of Nazareth in Israel. However, Messianic Jews are referred to in modern Hebrew as יהודים משיחיים (Yehudim Meshihi'im).
In Arabic-speaking cultures, two words are commonly used for Christians: Nasrani (نصراني), plural "Nasara" (نصارى) is generally understood to be derived from Nazareth through the Syriac (Aramaic); Masihi (مسيحي) means followers of the Messiah.
Where there is a distinction, Nasrani refers to people from a Christian culture and Masihi means those with a religious faith in Jesus. In some countries Nasrani tends to be used generically for non-Muslim white people. Another Arabic word sometimes used for Christians, particularly in a political context, is Salibi; this refers to Crusaders and has negative connotations.
Nasrani or Nasranee may also refer to the Syrian Malabar Nasrani people, a Christian ethno-religious group from Kerala, India, are a mixed race people of Chaldean, Malayali Brahmin, Syriac, Jewish and other Malayali Hindu Castes in decreasing percentage of ethnic ancestry.
In India Christians also call themselves "Isai", and are also known by this term to Hindus and others in south Asia. This is related to the name they call Jesus, "Isa Mesih".
In the past, the Malays used to call the Portuguese Serani which meant "followers of the Nazarene". The term Serani is used for the creole Christian community of Malaysia today.
The Chinese word is 基督徒 (pinyin: jīdū tú), literally "Christ follower."
Christianity by country
As of the early 21st century, Christianity has around 2.2 billion adherents. The faith represents about a quarter to a third of the world's population and is the largest religion in the world, with approximately 38,000 Christian denominations. Christians have composed about 33 percent of the world's population for around 100 years. The largest Christian denomination is the Roman Catholic Church, with 1.166 billion adherents, representing half of all Christians.