GR is ghost rating, a separately maintained rating system that is further explained here:
http://tournaments.webdiplomacy.net/theghost-ratingslist

Context might also matter in deciphering some phrases that may appear to be acronyms. Sometimes people abbreviate power names by the first letter and combine several to speak of groups of powers.

For example: if someone in a game speaks of a "GR alliance", they probably mean "Germany-Russia alliance"

Just to help clarify, "gunboat" is just slang for the "no in-game messaging" property of some games.

http://tournaments.webdiplomacy.net/community-help-pages/terminology

Unfortunately, the glossary in the link that I just posted is quite poor. I guess it's not really actively maintained.

There have been similar threads like this in the past. Here are a few:
threadID=518358
threadID=897624
threadID=876264

http://webdiplomacy.net/help.php
http://webdiplomacy.net/rules.php

DMZ - demilitarized zone. Do not send units.

NAP - Non-Aggression Act - not as permanent or obligatory as a formal alliance. Basically you agree to not attack or encroach on each others territories.

Non-Aggression Pact...

live game, starts in an hour!!!!!!!!!!!!!
password=swag
http://webdiplomacy.net/board.php?gameID=133242

Don't forget to put updog in the glossary

We have live games thread for these advertisements, ya know...

full press = you can send private messages and public messages
public press = every message you send is public
no press = you cannot send messages (these games are often called 'gunboat' games)
press = message(s)

'CD' stands for 'civil disorder', but in WebDiplomacy refers to two consecutive phases with no orders submitted; 'CD' is not used to refer to 'civil disorder' as defined by the rulebook (this is a board game), which refers to the rules that come into force when a player fails to submit orders or the condition of a country in such a state. Civil disorder per the rulebook basically refers to the same thing as the term 'NMR', which is commonly seen on WebDiplomacy: that is, just one phase without moves submitted. 'NMR' stands for 'no moves received'. The difference between one phase missed and two consecutively missed is important because a great power with two consecutive NMR's is judged on WebDipomacy to have an absent player: any user not already in the game can take over the position, the great power's vote is not needed for draw/pause/cancel unanimity and the player does not get a share of the pot at the end of the game in the case of PPSC.

NMR and the 'press' terms date from the days when Diplomacy was being played via USPS.

Stab is what you do when you attack someone without telling them, which is kind of the way to attack in this game. Just saying because if you don't get that you will likely not get into this game until you do...

Enemy: Someone you are currently fighting.
Ally: Someone you plan on fighting later.
Cunning master of the game: You when you stab an ally.
Bastard son of a talentless whore: Your ally when they stab you.

It would be great if a glossary could be added to the help page.

"Ally: Someone you plan on fighting later."

That's actually a good rule of thumb for a newb.

The other abbreviations/terms that sometimes get me are the "official" terms for formal alliances.

Juggernaut: An alliance between Turkey and Russia (so called because it cannot be flanked and is thus quite strong).

Western Triple: An alliance between England, France, and Germany. Sometimes abbreviated as EFG, or WT.

Central Powers Alliance (or simply Central Alliance): An alliance between Germany, Austria, and Italy. I've seen it abbreviated here as CPA.

Many of the opening names (and inspiration) can be found on the diplomatic pouch: www.diplom.org/Online/Openings/‎