Difference between 4x4 and TRD?

I have a Tundra SR5 4x4 but apparently that's not a TRD. What's the difference?

 

TRD was a package that had different shocks and maybe coilovers. Not sure about stock, but TRD package had bilstein shocks.

 

TRD packages come with different shocks and some have the sway bars .

 

Not sure if you mean the package or the TRD Pro trim level. Mine's an SR5 with the TRD Off-Road package, and from the brochure:

TRD Off-Road Package — upgrades standard wheels to 18-in. split 5-spoke TRD Off-Road Package alloy wheels and all-terrain P275/65R18 tires; includes trail-tuned Bilstein®
46 shock absorbers, engine skid plate, fuel tank skid plate, front tow hooks 1 (on 4x2 models; standard on 4x4 models), LED headlights and LED fog lights (on SR5 models only), TRD Off-Road floor mats 10 (on SR5 and Limited models only), and bedside TRD Off-Road decal.

TRD Pro is a different animal altogether.

 

TRD is driving terrain, 4x4 is driving conditions.