Get Taxonomy Term Title by it’s URL

This is far from trivial. URL processing is not straightforward and mostly buried in WP->parse_request() which is not popular to reuse.

There is more useful url_to_postid() function, but it’s limited to posts and does not process URL to other things.

If really necessary this would take fork of that function to deal with terms. However more practical solution would probably be to pass some extra data in some form and don’t mess with URL at all.