Earth Supremacy Question

[deranged]

So Earth Supremacy states, "In addition, you gain a +1 insight bonus on melee attack and damage rolls whenever both you and your foe are touching the ground." How is ground being defined? I know it is nitpicking, but I feel there is a difference between the ground as in any surface that is part of the gravitational plane (so the plowed field, the floor of an inn, etc) and the ground as in any natural occurring surface (grass, natural rock, sand, etc).

[Deadmanwalking]

It applies whenever the -4 penalty doesn't. Or at least that's my interpretation based on the Marid's similar ability. So whenever their opponent is flying or swimming. If they are standng on a solid, ground-like, surface, the Shaitan gets his bonus.

[Starglim]

The solid surface of the planet. A plowed field, the floor of a cave or of an excavated tunnel, a plowed field above a tunnel or a flagstone road laid on packed earth are ground. The upper floor of an inn, an unworked slab of rock that has fallen across a canyon or grass growing in dirt spread on a roof are not.

Deadmanwalking's interpretation also seems reasonable and certainly simpler to judge.

[LazarX]

Basically if the surface the combatants are standing on is one that an Earth elemental could earthglide through, the bonus counts.