What is consubstantial?

Consubstantial is a theological term used to describe the relationship between the Father, Son, and Holy Spirit in the Christian doctrine of the Trinity. It means that the three persons of the Trinity share the same substance or essence, and are therefore one in their divine nature. This term is based on the Nicene Creed, which states that the Son is "consubstantial with the Father" and the Holy Spirit is "consubstantial with the Father and the Son." The concept of consubstantiality affirms the unity and equality of the Trinity, and is a fundamental belief of many Christian denominations.