HolyTrinity

Historically, as evidenced by the Nicene and Apostle's Creeds used by most of Christianity, the Holy Trinity refers to what Christians say are the three aspects of God, the Father, the Son, and the Holy Spirit.

The Father is the God who acts throughout the Old Testament and talks to Christ in the New Testament.

The Son is Jesus, whose sacrifice on the crucifix either ransomed souls from hell or opened the portal to heaven for whoever wants to go, depending on whom you ask. He was both God and man, not considered to be some kind of phantasm or soulless possessed being, but was just like other humans except for also being God.

The Holy Spirit is the little angel sitting on cartoon characters' shoulders, telling them the proper way to deal with the universe. It is within everyone, the part of God that communicates directly with humans.

All three parts are widely held to be coeternal, of the same substance, and yet inexplicably different. All are considered to be present at each stage in history; the Trinity just shows the appropriate character at a given point.

Because I am not an expert on Christianity, I can't help much here. I suspect that the description of Holy Spirit as "the little angel sitting on cartoon characters' shoulders" could probably be explained more accurately, although surely not more vividly. :-) Please delete this note whenever you've made some change, o kind passerby.