A Christian ( pronunciation (help·info)) is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus Christ. "Christian" derives from the Koine Greek word Christós (Χριστός), a translation of the Biblical Hebrew term mashiach. 

There are diverse interpretations of Christianity which sometimes conflict. However, "Whatever else they might disagree about, Christians are at least united in believing that Jesus has a unique significance." 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." It is also used as a label to identify people who associate with the cultural aspects of Christianity, irrespective of personal religious beliefs or practices. 

According to a 2011 Pew Research Center survey, there were 2.2 billion Christians around the world in 2010, up from about 600 million in 1910. By 2050, the Christian population is expected to exceed 3 billion. According to a 2012 Pew Research Center survey Christianity will remain the world's largest religion in 2050, if current trends continue.
How many Christians are in the world as of 2010?
Do interpretations of this religion conflict?
How many were there in 1910?
Is this the largest religion?
It is based on the teaching and life of whom?
What word is it derived from?
How many will there be by 2050?
Who did a survey that found it will be the largest religion in 1050?
Which culture is the word derived from?
Is Christianity a monothiest religion?
Can the word be used as an adjective?
What are all Christians united to believe?
2.2 billion
2.2 billion
yes
sometimes conflict.
600 million
600 million
largest religion in 2050
largest religion in 2050
Jesus Christ
Jesus Christ
Christós
Christós
exceed 3 billion
exceed 3 billion
Pew Research Center
Pew Research Center
Koine Greek
Koine Greek
yes
monotheistic
yes
adjectivally
Jesus is unique
Jesus has a unique significance