It has nothing to do with English. That's how trinitarians have been describing the "godhead" since its development. In Greek it's three hypostases in one ousia - which as I've already explained leads to the teaching of three gods.You're going to rely on English to try to overthrow the teaching of the Church for well over 1,000 years before English even existed as a language?!?
You say that like it actually means something. Well I hope you're not a Protestant because up until a few centuries ago there was no such thing as a Protestant. Such as thing was never even imagined. For about 1,200 it was the teaching of the church that if you broke off from "the church" you were a heretic. Also, the reason the doctrine of the trinity has been accepted for the past 1,700 years is due to trinitarians silencing their opponents however they could including excommunicating, torturing, murdering, and imposing any other form of punishment on non-trinitarian Christians and non-Christians.to try to overthrow the teaching of the Church for well over 1,000 years before English even existed as a language?!?