[@Fallenreaper] Well the conditions under which one develops powers or becomes Mutant or Meta describes those subcategories. I can also see where the two might be used interchangeably by an uninformed mass, just as people ignorant to different magical practices label all practitioners as sorcerers, mages, witches, etc. To those who don't know their definitions, these words all mean the same thing. 

Also, "Meta-human" might be a larger umbrella term under which mutant, hybrid (such as humans with alien DNA), and etc. would classify as subcategories of Meta.