Can someone explain exactly what everything means

For example,

18x9 +25

18 is diameter of wheel, and 9 is wheel width

25 offset is what, how far out the wheel comes from were the its attached to the hub??

http://www.skylinesaustralia.com/for...490.html&st=40

I want something like esky mads stance, see his 1st post, what wheel size should I be looking for? Ive never seen +11 offset?