Oneness Pentecostalism, also known as Apostolic Pentecostalism, is a movement of Christianity that split from the Pentecostal movement, at around 1914. Followers believe that the Bible was inspired by God.
"Oneness" means that they believe that God is one being, not three persons (like in the Trinity doctrine), and that Jesus is God in human flesh – fully god and fully human. This makes them different from most Unitarians who say that the son of god was only man. "Apostolic" means that they follow the Apostolic doctrine (by the 12 Apostles in the early Church). "Pentecostal" means that they put an emphasis on the moving of the Holy Spirit (like speaking in tongues) as was done on the Day of Pentecost.