Rib-eye steaks can be boneless or bone-in, meaning the steak contains a piece of rib bone. The bone may extend inches beyond the tip of the rib-eye muscle, or be trimmed more or less flush with the meat. You may see a bone-in rib-eye labeled as "rib steak."
The bone adds flavor and moisture, but it can make cooking the steak more difficult. The meat next to the rib cooks more slowly, so by the time that meat reaches medium-rare, other parts of the steak might be closer to medium. Fortunately, boneless rib-eye steaks are pretty much the norm.