but as in all things there are conventions.
A thread is something that you start when you have a question to ask, or a piece of relevant news you want to share with everyone. It's called a thread because all the subsequent contributions are expected to follow the same thread of information - be 'on topic' if you like.
A post is a contribution you make to a thread - not necessarily your own thread.
So, you post a thread, and you post a post to a thread. Is that clear?
You be careful too, I'm a 6' 1", 16 stone Welsh computer consultant.