best friend for awhile, or someone that you've befriended because you have to/for selfish purposes and as soon as you don't have to see them a lot they will no longer be a best friend.
BEST FRIENDS FOR AS LONG AS POSSIBLE--- two people who go to eachother for everything and sit at starbucks together with nothing in particular to talk about and play phase 10 and eat applebees everyday. They are the two people you expect to see together all the time and when you see one, you automatically assume the other is around somewhere.