Men’s boxers and briefs are both types of underwear, albeit of different styles and coverage. Men’s brief underwear extends just below the hips, only covering the important bits and leaving the legs free.
Boxers, named after the athletic shorts boxers wear in the ring to face each other, are looser forms of undergarments, covering the upper parts of the legs.
A third option for men’s underpants are boxer briefs, a combination of the two, featuring boxers’ shape and styling with the snug fit of briefs.