I am not familiar with "trading title", but I think that "trade name" could mean two things: 1. The name you use at work (which may or may not be the name you use in your personal life) 2. The name of your profession (i.e., teacher, lawyer, doctor, entrepreneur, accountant...) You could also use the term "trade name" in the second case mentioned above, but I don't think I've ever heard "trading name". That said, I don't work (and have never worked) in business, where it might be common...