For any newer players wondering what the heck we're talking about, hopefully this helps. Additions welcome.
Yes, I will expand this because there's a lot more to add.
2-Ship: A no longer legal archetype centered around a Quasar, a Star Destroyer, Governor Pryce and a large squadron wing.
AA (or AAA, AS): Anti squadron attack (usually that of a ship.)
Acc: Acclamator or accuracy
Ackbar Slash: A tactic consisting of moving between two targets and firing both broadsides.
ACM: Assault Concussion Missiles
AF2(or AFII, AFMK2, AFMKII): Assault Frigate
AFFM(!): The All Fighters Follow Me! fleet command.
Alpha strike: An initial hard hitting squadron command performed against other squadrons.
AMG: Atomic Mass Games
APT: Assault Proton Torpedoes
Arq: Arquitens Light Cruiser
AST: Auxiliary Shield Techs
BC: Boosted Comms
BCC: Bomber Command Center
BTA: A now-obsolete combination of Avenger and Boarding Troopers.
BTs: Boarding Troopers
CF: Concentrate Fire command.
Chirpy: Admiral Chiraneau
DCaps: Disposable Capacitors
DCO: Damage Control Officer
Deci: VT-49 Decimator
DeMSU: An Imperial MSU fleet centered around Demolisher (see MSU.)
DTT: Dual Turbolaser Turrets
EA: Enhanced Armament
ECM: Electronic Counter Measures
EF(!): The Entrapment Formation! fleet command.
EHB: Expanded Hangar Bay
EST: Expert Shield Tech
ET: Engine Techs
FAQ: FFG's Frequently Asked Questions document for Armada, containing rule clarifications.
FC: Flight Controllers or Flight Commander
FCT: Fighter Coordination Team
FFG: Fantasy Flight Games
Fish Farm: A somewhat outdated archetype centered around squadrons with the Strategic keyword, an Ackbar MC80 with minor support ships, and an objective-oriented playstyle.
FLGS: Friendly Local Games Store
Force Multiplier: An effect or asset that increases the power of other assets; for example, Yavaris, Plo Koon, Home One, fleet commands.
FT (or Flesh Torps): Flechette Torpedoes
GH: Gallant Haven or Garel's Honor
Glad (or GSD): Gladiator Star Destroyer
GT: Gunnery Team
HH: Hammerhead Corvette
HIEs: Heavy Ion Emplacements
ICB: Ion Cannon Batteries
IF(!): The Intensify Forward Firepower! fleet command.
ISD: Imperial Star Destroyer
Lib: Liberty variant MC80
Lifeboat: The now illegal practice of using a flotilla as a flagship, usually well out of harm's way.
LMSU: An archetype centered around many small ships and a single large ship.
LS: Leading Shots
MMJ (or MJ): Maarek Stele, Morna Kee, and Colonel Jendon.
MSU: Many Small Units, an archetype centered around large numbers of small ships.
Muni: Munificent-class Frigate
Neb: Nebulon-B Frigate
OE: Ordnance Experts
PDR: Point Defense Reroute
Pulsetap: A list centered around the (often futile) strategy of triggering Overload Pulse before attacking with Avenger. Now obsolete due to nerfs.
QBTs: Quad Battery Turrets
QTCs: Quad Turbolaser Cannons
RHD: Reserve Hangar Deck
RNG: Random Number Generation; often described as a force affecting actions such as die rolls that carry an element of chance.
RNGesus: A mythical deity of chance, esp. in gaming.
Satovation: A swingy but high damage Nebulon with the Salvation title included in a Sato fleet.
Squid: MC30 frigate
SSD: Super Star Destroyer
STM(!): The Shields to Maximum! fleet command.
Swingy: Prone to high variance in results; for example, unmodified red dice.
Tanky: Durable, capable of enduring punishment.
TEA(!): The Take Evasive Action! fleet command.
TFA: Task Force Antilles
TFO: Task Force Organa
TRC: Turbolaser Reroute Circuits
TRC90: A CR90A with Turbolaser Reroute Circuits.
VSD: Victory Star Destroyer