This list will attempt to explain some of the more common jargon found within WoWP that is not always readily apparent to the newer player.
AA - Anti-Aircraft gun. These fire machine gun or autocannon rounds. Both AA and AAA are shown as yellow triangles on the ground.
AAA - Anti-Aircraft Artillery. These fire shells that produce clouds of shrapnel (flak). Both AA and AAA are shown as yellow triangles on the ground.
BnZ - See Boom and Zoom
Boom and Zoom - Airplane or play style that uses high altitude and diving attacks to engage enemy planes.
GA - Ground Attack aircraft
GT - Ground target
HF - Heavy Fighter
LF - Light Fighter
MRF - Multi-Role Fighter
Lemming Train - When most (or all) of the planes in one team simply follow other planes in one direction and engage the opposing force one at a time.
MM - Match Maker - the system used for building teams in public matches. It is a sophisticated algorithm that follows a set of rules to select teams from the "wait" queue that are as evenly balanced as possible. Teams "matched" are dependent on the planes in the "wait" queue and.
Mod - A WoWP in-game or forum moderator, or a visual or audio modification to one's game client.
Nerf - To weaken an equipment, vehicle, or module by modifying its stats. It's done by programmers to rebalance anything they feel is too powerful and thus unbalanced.
NS - Nice shot
o7 or o> - Salute. Often used to greet friends and fellow clan members. The "o" represents a person's head, and the "7" or ">" represents the person's arm, making the salute.
Seal Clubber - A player, who despite having many battles, still plays mostly low tier vehicles.
Team Killer - Someone who deliberately kills or damages a friendly plane.
TnB - See Turn and Burn
Turn and Burn - An airplane or play style that uses maneuverability to engage enemy planes.
Guns can be mounted in many locations on a plane. The game indicates where using a letter in parenthesis. Here's what they mean:
(S) = Synchronized. These are mounted flush with the fuselage at the front of the plane, on single engine airplanes. Thus, they literally fire through the propeller. This requires that they be synchronized with the propeller to only fire between the blades. It works pretty well, but reduces the rate of fire somewhat compared to other mounting locations.
(W) = Wings. Everyone can probably guess this one. These are mounted in the wings. Wing mounted weapons are almost always mounted in even numbers.
(C) = Cowling. These are actually mounted in the same location as Synchronized, but on aircraft that don't have a propeller on the nose. These might be twin-prop, rear-prop, or jet powered. In any case, the only difference is they don't have the rate of fire reduction.
(H) = Hub. This is a single weapon mounted dead center in the middle of the propeller cone, with the propeller spinning around it. This ingenious mounting method avoids having to synchronize fire with the propeller on single-engine front-mounted propeller aircraft. For engine designers this was probably a pain to design since the engine has to be designed with space for the weapon, but for pilots it works great.
(O) = Outboard. These are mounted to the bottom of the wings, usually in some type of aerodynamically shaped pod. Typically used when the weapon is too large to fit inside the wing.