Not knowing any details, it could mean that Mr. Zimmerman was atle to generate enough distance to clear the weapon and place a round. It doesn’t take much, couple yards and there is still marks made by powder and carbon. Much beyond 3 yards, the marking goes way down.
Anything further than two feet, the powder won’t be on the body, not nearly as much as if it’s closer than feet.
In near-contact wounds, the muzzle is not in contact with the skin, but is very close. In this case, the powder grains do not have a chance to disperse and leave a powder tattooing. The entrance wound is surrounded by a wide zone of powder soot, and seared, blackened skin. In intermediate-range wounds, the muzzle is held away from the skin but close enough that it still produces powder tattooing. This type of wound is also characterized by numerous reddish-brown to orange-red lesions around the entrance to the wound. Finally, distant gunshot wounds leave no marks other than those produced by the bullet perforating the skin.Of course, the MSM won't define the term, thus leading the viewer to think that "intermediate range" is between 7 and 50 yards. Zimmerman most likely fired with the muzzle within inches of Martin.