I would question what "Someone Else" has said. In Berne Convention countries, at the end of the 31st December in the year 70 years after the death of the author, copyright expires. I know of no case on the effect of international time zones in this context. In most cases (but not, in the UK, works in which copyright was already running on the commencement of the Copyright Designs and Patents Act 1988) copyright is a particular jurisdiction may be truncated by the expiry (but not seemingly prior termination or forfeiture) of copyright in the work in its "country of origin". This gets particularly exciting with US works because teh US used to forfeit copyright for all sorts of reasons that the rest of the world did not.

Then the work is "out of copyright". If a work is "out of copyright" or if for some reason such as the author and place of first publication not qualifying, then it is often referred to as "public domain" - an expression of which I have never fully approved because it is not defined in the Copyright Designs and Patents Act and so is of debatable meaning in the UK. I have tried since I first qualified as a solicitor and started to specialise in copyright in 1976 to be consistent in this usage, and while I have been called "pedantic" in this I have never been called "wrong".

If anyone can point me to any UK court judgment actually using "trad" or "traditional" in the way Someone Else (I think) suggests I would be interested. I am not aware of it being used in that way in the recent "Procul Harum" judgment which did debate the similarity of "Whiter Shade of Pale" to J. S. Bach's "Air on a G string".

It is, I suppose, my legal background that tends me to think of a "definition" as being set in stone, for certainly in that context if statute or common law provides a specified meaning for a word or phrase, then a use that is inconsistent with that specified meaning is, quite simply, and without possibility of argument, wrong.