Trinity means three, so when we discuss the Holy Trinity we mean the Father (God), Son (Jesus), and Holy Spirit (sometimes referred to as the Holy Ghost). Throughout the Bible, we are taught that God is one thing. Some refer to him as the Godhead. However, there are ways that God has chosen to talk to us. In Isaiah 48:16 we are told, "'Come closer, and listen to this. From the beginning, I have told you plainly what would happen.' And now the Sovereign Lord and his Spirit have sent me with this message."
We can see clearly here that God is talking about sending his spirit to talk to us. So, while God is the one, true God and is the only God, he uses other parts of himself to accomplish his goals. The Holy Spirit is designed to speak to us. It is that little voice in your head. Meanwhile, Jesus is the Son of God, but also God. He is the way God revealed himself to us in a way we could understand. None of us can see God, not in a physical way. And the Holy Spirit is also heard, not seen. However, Jesus was a physical manifestation of God we were able to see.
Trinity season (Ordinary Time or the Season after Pentecost) is the longest season of the Anglican liturgical cycle. It lasts from the week after Pentecost to Advent. It is during this season that we study the life of Christ as he completely obeyed the commands of the Father, as he taught his disciples, and as he ministered to the people around him. Green is the colour used in Trinity. During this season, many worship traditions follow readings that highlight the work of the Holy Spirit in the Church's mission, although the various Sundays are not connected by a particular theme.