OFT = Open Flash Tablet

OFM = Open Flash Manager 

This is the Windows based software used to load tunes files and

OTS = Off-The-Shelf

This refers to a tune file that is "off-the-shelf", or pre-made for specific upgrades already fitted to your engine. 

ROM = Read Only Memory a.k.a. Tune file or Calibration File 

This is the program that is written to or read from your ECU's memory.

Tune, Program or Calibration = Please read ROM above.

ECU = Engine Control Unit (Engine Computer)

Flash, Reprogram, Upload = This is what we call the process when we write a new ROM to your ECU.