No difference. The difference is between Solvent based and water bourne (water based). Most water based pants are acrylic, latex or tempra paints and have substancially lowe VOC levels than solvent based (epoxy based as well). Contrary to popular belief, water based paints are NOT inherently nontocix so don't assume.
Here is why I asked the question in the first place (from Createx):
Wicked Colors perform unlike any other Createx product. Unlike Createx Airbrush Colors which are water-based, Wicked Colors are waterborne meaning the colors contain solvent for exceptional performance.
So are "waterborne" paints a combination of solvent and water?