Trinitarianism is the Christian doctrine that God exists as three persons (Greek hypostases) but is one being. The persons are understood to exist as God the Father, God the Son (incarnate as Jesus Christ), and God the Holy Spirit, each of them having the one identical essence or nature, not merely similar natures.
Or, in this season of Supernatural, Dean the parent, Amara the child, and Amara-of-the-Whirlwind the Holy Spirit. Three separate entities, and yet all of a single essence.
Trinitarian theology gives me a headache – seems to me a lot of hyper-rationalizing and over-parsing of an idea better explained by repeating that God is omnipotent and ineffable, and maybe some vigorous hand waving. (plus I was hoping that we’d be getting Charlie as the risen Christ about now, so them making trinitarian motions instead is kinda disappointing.)