in the new testament, there are three beings who are said to be god in different forms: the father, the son, and the holy spirit (also known as the holy ghost). this is called the trinity. although the word "trinity" is not in the bible, the word used for god in chapter one of genesis is actually plural, and the phrase "in the name of the father, son and holy spirit' is used in the new testament, (e.g. matthew 28:19). another word that christians believe has exactly the same meaning as "trinity" is the word "godhead", which "is" in the bible.