When my company buys the ticket, I just worry about the schedule. When I buy the ticket, I mostly worry about the price.

From browsing this board, it appears that the class of fare you get could be very important as to whether you can upgrade. I think I know what F,J, and Y are, but there's a gazillion other fare classes down to and including Z.

Are the abbreviations industry-standard or are some of them airline-specific? Where can I find out what they all mean? And please, no comments about not being "worthy" if I don't have this info at my fingertips.