Previously I usually have no idea of what resistance means, today I finally get it. So the expression of resistance, can be written as this:

R = V / I

If you think about it, resistance is a rate, meaning Volts per Current. This could be explained as the amount of volt, required to let a current through some point, and could be further explained as The amount of push force required to let 1 coulumb of charge through in a second.

Anyway, that was something that I have never through about before.