A friend is known to be someone that you will have a strong bond with. This is someone that you have spent a lot of your time with. You can tell your friend some of your deepest, darkest secrets, and you know that you will not be judged for it. It is also your friend that you can share some of your special moments with.
This is different from an acquaintance. This is someone that you may have met, but you are not too close with. There are times when you would say hello but not enough to actually start deep conversations with them or even spend time with them. Some of the friends that you have may start out as acquaintances.