So, as you well know, the whole idea of definitions is to tear them down as you build them up. A definition isn't very interesting if it doesn't have fringe cases. This is true when it comes to even banal things like the Calendar. My local sub shop has a Taco Tuesday special but they wouldn't give it to me on account of it not being Tuesday today. I argued that Taco Tuesday is merely the name of the special, not an exclusionary clause. They counterargued that I will have to come back on Tuesday.
A similar concept applies to Friday the 13th. I've long known that Friday the 13th is especially bad when it falls on a Monday, so I did some rigorous studies and now I can rank all the "Friday the 13ths" that being the name of the event and not an exclusionary clause.
1. Monday the 13th
2. Friday the 13th
3. December 24th
4. Tomorrow
5. 5 lightyears
6. an elephant and a giraffe walk into a bar
7. why are you still reading this?
