As you mentioned, the first part of the name may try to relate to the type of PVP from the server, but thats not a general rule and is not even THAT common, most servers just have random names, like: PYRA, QUINTERA, OLERA, etc....
The only rule when it comes to server names is the LAST part:
- BRA = South American Server: inaBRA, lutaBRA, nossoBRA, genteBRA
- ERA = North American Server: wintERA, solidERA, quintERA
- None of the above = European Server: antICA, bellUMA, boNA