Reminds me of Elon Musk's hatred of acronyms: https://gist.github.com/klaaspieter/...eae5cdd4ea1764 Acronyms rarely provide more benefit than downsides mostly because there's no control on who gets to make them and they just spiral out of control. While a lot of users here are flying experts and are very at home with these acronyms, there are obvious situations (like this one) in which there's a huge likelihood an OP might not know. It's not really hard to say "You can use a GUC (Global Upgrade Certificate)" if you're taking the time to respond to a post.