1. Something that has gone awry or not as one expected, with the implication that it is the product of bad luck. I can't believe you didn't get that part in the play. What a bad break.Shelly had a bad break this morning when her car wouldn't start.
2. A fracture of a bone that is particularly extreme or not conducive to proper healing. Unfortunately it was a bad break, and your leg will have to be in a cast for six months.