I'll give better explanations and alphabetical order eventually.
Car
SAM - Signal Acquisition & Actuation Module - Footwell fusebox in newer smarts.
ZEE - Zentrale Einschub Elektrik (Central Electric Module) fusebox in older smarts.
AMT - Automatic Manual Transmission.
SE Drive - Sequential Drive - The gear stick module.
TAN - Transaction Number, a code for activating extras on the smart like paddleshift and auto.
TIK - Turbo Induction Kit - Pipe between the air filter and the turbo.
OBD - On Board Diagnostics - A sockets connected to the ECU.
ECU - Electronic Control Unit - The smart's brain.
MAF - Mass Air Flow - Sensor that measures the air volume entering the engine.
MAS - Mass Air Sensor - Sensor that measures the air mass entering the engine.
HSA - Hill Start Assist - Brakes hold for a fraction of a second to stop you rolling.
EBD - Electronic Brake Distribution - Brakes selective wheels to improve stopping.
ESP - Electronic Stabilty Protection - Limits power if the car slides.
BCS - Boost Control Solenoid - Controls the bypass wastegate.
MAP - Mass (or Manifold) Absolute Pressure - Measures the air pressure.
EGR - Exhaust Gas Recirculator - Feeds hot exhaust air into the engine.
VIN - Vehicle Identification Number - Unique number stamped on all cars.
ABS - Antilock Braking System - Stops you skidding.
Trust - The oldest version of ESP.
Trust+ - An update to Trust.
MHD - Micro Hybrid Drive - Stop/start on the 451.
DPF - Diesel Particulate Filter - Emissions reducing device on Euro 5 diesel 451.
Dealer
ESKULAB - Elektronische Kulanzabfrage - A fair trade query.
WIS - Werkstatt (Workshop) Information System - Merc workshop manual.
EPC - Electronic Parts Catalogue - parts catalogue on CD.
MEG1.0 - It's what smart call the ECU in a 600cc smart.
MEG1.1 - It's what smart call the ECU in a 700cc smart.
ME-SFI - It's what smart call the ECU in a 999cc smart.
Modding
ICE - In Car Entertainment, stereo, dvd, lcd screens etc.
LCD - Liquid Crystal Display, flat screens.
DVD - Digital Versatile Disc.
TIK - Turbo Induction Kit - Pipe between the air filter and the turbo.
DV - Dump Valve, a valve that opens to purge excess boost.
Info
450 - Generation 1 smart fortwo, mk1 to mk7. 1998 - 2006.
451 - Generation 2 smart fortwo. 2007 - 2015.
C453 - Generation 3 smart fortwo. 2016 onwards.
452 - Roadster. 2003 - 2007.
454 - Forfour. 2004 - 2006.
W453 - Generation 2 forfour. 2016 onwards.
Nearside - The left side of the car as you sit in it facing forward.
Offside - The right side of the car as you sit in it facing forward.
Left - <---- That way.
Right - This way ---->.