What is "spirit" in Holy Spirit?

Jesus taught the woman of Samaria that "God is spirit" . The answer to the Penny Catechism Q17. *What is God?* is **God is the supreme Spirit**, *who alone exists of himself, and is infinite in all perfections.* As the Third Person of the Blessed Trinity, the Holy Spirit is God and consubstantial with the Father and the Son. A diagram as one below is sometimes used to explain the mystery of the Blessed Trinity. This is where it gets confusing for me. If each of the persons is God, then from the foregoing we can say > The Holy Spirit is the supreme Spirit. Since the Father and the son are each also the supreme Spirit but not the Holy Spirit, what is "spirit" in the Holy Spirit and how is it different from "spirit" in the supreme Spirit? Catholic perspective preferred but any others welcome from Christians who believe in the Blessed Trinity.