Oh, and almost forgot this. Trinity is shorthand as far as I'm concerned for Father God, Jesus and the Holy Spirit. It is not a necessary term as the essentials of it are in the Bible and stand on their own. I'd just as soon reference the three of them than use the word unless I were writing it all out, which is the only time I bother with it. So, in short, it is not in the Bible, nor does it need to be. I'm not certain I really understand the point behind someone coming up with the term to be quite honest - I don't see that it is needed.
It has been pointed out already, but I just want to amplify. There is a very specific meaning of the Trinity that you have shown no idea of understanding. Trinity could just as easily mean three faces of one God, or Three Gods acting together. It means three persons in one divine nature. It means something today and it had meaning when the heretics were fought and the term defined. To sit here in the 21st Century and say "I don't see that point behind coming up with the idea" is, well, typical. Typical anti-historical and anti-intellectual, that is.
SD
Technically, this would be tritheism.