Boston butt is the traditional name in United States. Outside that tradition, butchers carry comparable pork cuts under different names — sometimes the same anatomical piece, sometimes a close cousin. The alternatives below are grouped by country so you can match what your local butcher actually carries.
Some country-style ribs are cut from the upper shoulder (Boston butt) rather than from the loin blade end. Both share the same heavy marbling and long-cook tolerance.
Both are from the shoulder and suited to long, slow cooking, but the butt is fattier and more forgiving while the picnic includes the leg bone and has a stronger flavour.