The word "Trinity" comes from the Latin noun "trinitas" meaning "three are one." The Trinity expresses the belief that God is one Being made up of three distinct Persons who exist in co-equal essence and co-eternal communion as the Father, Son and Holy Spirit.
The doctrine or concept of the Trinity is central to most Christian denominations and faith groups, although not all. Among churches that reject the doctrine of the Trinity are The Church of Jesus Christ of Latter-day Saints, Jehovah's Witnesses, Christian Scientists, Unitarians, the Unification Church, the Christadelphians, and Oneness Pentecostals, as well as others.
• More about Faith Groups that Reject the Trinity.
Although the term "Trinity" is not found in the Bible, most Bible scholars agree that its meaning is clearly expressed. These are some of the verses expressing the concept of the Trinity - Matthew 3:16-17, Matthew 28:19, John 14:16-17, 2 Corinthians 13:14, Acts 2:32-33, John 10:30, John 17:11&21. For an in-depth study of the Trinity doctrine visit GotQuestions.org on What Does the Bible Teach About the Trinity?