When you're talking about an outdoor environment, are you allowed to use floor? Or do you have to use ground instead? Thanks for your help.
yes, a 'floor' is usually something that is constructed, whether indoors or out [a porch has a floor, but is outdoors, not 'inside']... though one can refer in general to the floor of a cave, canyon and such, in referring to what a person stands on out of doors, it should be the 'ground' or 'dirt/earth/lawn/whatever' and not 'floor'...
As maia said in reference to something general floor would be alright such as floor of the cave, or floor of the canyon. Specifically as someone is standing on something you shouldn't use floor unless it is in fact a floor. Caleb