Although the Italian term (Gran Tourismo)DOES sound Hip to pronounce and is still used by most of its manufaturers, Grand Tourer s actually a body style classification that includes 2 door, 2 or 4 seat arrangment, and lineage/genes connectins it to a race/track version.
Grand Tourer, the term is pretty self explanatory, although it been taken up by various manufacturers to somewhat enhance the appeal of their sportier models, but they don't Just mean ANYTHING.
GTO -Gran Turismo Omogolata (Homlogated)
GTi - Grand Tourismo Injection
GTTi -Grand Tourismo Turbo Injection
GTA, GTJ, GTV, GTC used by Alfa for various models,
GT-R - Gran Turismo - Racing
GTiR - You figure it out
and so on and so forth.