These are terms used on Kali, The Zone, and other Multiplayer Networks

A
alt-m
Turn off your music
B
C
cat
Refers to a balista or catapult.
CLOSED
This is what you will see if you come into a room that has a private game. So leave politely. This rarely happens but be prepared and know its nothing personal.
D
Doubling Up
Having peasents repair a building while it's built.
F
Fat boys
Ogres. See Rats
FFA
Free For All' It means that everyone is on their own. It is understood that no one will have secret alliances. Yet these do happen sometimes
First contact
Means that you ally with whoever you come into contact with first.
G
gg
Good Game. It's what you say when you're losing or when your beating the living tar out of somebody and you don't want them to hold a grudge.
GOW
Garden of War built in pud
gp
Go Private. You only send messages to your ally
M
Money Train
Peons getting gold "in the money train"
N
NEWBIE
A Kali player with very little experience
O
Open
This is the polite thing to say when entering a room. It tells the game host that you want to play but want to make sure that you don't intrude on a private game. If the host says no or closed. Leave politely. You would want likewise from him.
P
POS
Plains of Snow built in pud
R
Rats
An affectionate name for Knights or Paladin's, because they look like little rats.
S
sappers
Refers to Sappers and Demo squads
smurfing
A Good player that plays for fun
T
TVB
This stands for 'Top VS Bottom'. The players are evenly divided in half from top to bottom and they are then against each other.
W
Wood Train
Group of peons getting wood