[TigersEye]

But how do you define space? All words are concepts.
What concept does the word space define?

[FormerLurker]

What concept does the word space define?

In a intuitive sense, space IS the distance between objects, or distance that an object may travel.

Then again, what is distance?

It is just what we perceive. That which exists beyond what we perceive intuitively is great, and is the reason why Physics exists, to describe the nature of the Universe.

[FormerLurker]

To get less esoteric, let me relate this. That which we perceive as space might just be Something that we can't see or feel. Just as a fish in water might not perceive the fact that it is in a medium that we call water, it is nonetheless in water. As fish in water, we might not perceive that which is something more than nothing, but we attach the word "space" to that medium.