Lamb Chump Chop is the traditional name in United States. Outside that tradition, butchers carry comparable lamb 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.
Adjacent cuts from either side of the same joint — the chump chop is the meatier, slightly fattier neighbour of the loin chop and grills identically.
The chump is the rump end of the leg, so leg steaks cut from the top of the joint are the nearest larger-format substitute.