Common terms used on this forum

9C1 - RPO code for the police package
B4U - "Sports" package on the caprice, pretty much the tow pak
BBB - Black
Chip - A Programable Read Only Memory "chip" used in the PCM on TBI motors. LT1 cars can use a "piggy back" chip, which plugs inline
DCM - Dark Cherry Metallic, paint
DGGM - Dark Green Grey Metallic, paint
ECU - aka PCM, Engine Control Unit
EFI - Electronic Fuel Injection
F40 - heavy duty suspension on the '94 cars
FE1 - RPO for the dynaride, aka SOFT suspension
FE2 - RPO for the Gran Touring suspension, aka Heavy Duty suspension
FSM - Factory Service Manual
G80 - Regular production code for Posi-traction
IAC - Idle Air Controller
KM - Knock Module. Located in the PCM behind a trap door, basically a filter for the Knock Sensors
LDM - Light Driftwood Metallic (tan, or gold)
LO3 - Throttle Body Injected 305, Used in cars before 94, RM's Had them in 91
LO5 - Throttle Body Injected 350, Used in cars before 94, All RMS's had this motor.
LT1 - Muti-port Fuel Injected 350, used from 94-96 in all B-body's, and 93-97 in F-body's
LT4 - Muti-port Fuel Injection 350, LT1 in a special trim(330hp) in 96 Gran Sport Corvette's.
L98 - Tuned port injected 350, used in sports cars before the LT1 came along
L99 - Multi-port Fuel Injected 265, used from 94-96 in caprice sedan's
MAB - Medium Adriatic Blue
MAF - Mass Air Flow Sensor
MAP - Manifold Absolute Pressure sensor
MPFI - Multi-port Fuel Injection, injector for each intake port
OBD-I On Board Diagnoistics 1, used before 1996, as the system of Engine control
OBD-II On Board Diagnoistics 2, used from 1996+. A more complex PCM system, and more sensitive.
PCM - Powertrain Control Module, basically the brain box the engine/trans
RM - Roadmaster
RMS - Roadmaster Sedan
RMW - Roadmaster Wagon
RPO - Regular Production code
SS - Impala SS, or when said "SS shocks", Monroe "Severe Service" shocks
TBI - Throttle Body Injection, looks like a carb with 2 injectors
TPI - Tuned Port Injection, injector for each intake port, long "tuned" intake runners
TPS - Throttle Position Sensor
V92 - Regular Production Code for the Towing package
VATS - Vehicle Anti Theft system, that lil chip in the square key
WB4 - Factory Wood paneling free

Can't think of any more. if you guys have more to add, let me know.

F40 is the heavy duty suspension on the '94 cars.
TCC is the torque converter clutch. The torque converter is electronically controlled by solenoid(s) in the valvebody which can force it to lock at highway speeds, lowering engine rpm, transmission temperature and improving gas mileage.
PCM - powertrain control module (engine computer)
PCS or EPC solenoid (pressure control solenoid) or Electronic Pressure Control solenoid - controls transmission hydraulic or "line" pressure.

1A2 - special service pkg avail on 91-95 Caprice wagons (aka 'cop wagons')
OCC - Olds Custom Cruiser

BBW - B-body wagon (or fat girl your choice)
TLA - Three Letter Acronym