A person who wouldgive you the shirt off his back if he doesn't want to wear it anymore. A Bro is a person who will bendoverbackwards to help you bend someone overbackwards. In short, a Bro is a lifelong companion you can always trust to be there for you, unless he's got something else going on.
You really helped me out of a tight spot man. You are my Bro for the rest of time.