We have the technology for at least 6 concurrent alliances (A-F) (BA/Eureka thread)

[Reynhart]

I think it's just to make it easier for you to know you're in an alliance. I like to think of them as being short for Alliance Party A, etc.

I'd say seeing 2 to 5 other "Parties" in your HUD should be enough to understand that you're part of an alliance, regardless of what they're called. In the end, the terminology is not really the core of the issue