Pork Sirloin Roast is definition no. 410 A in the Institutional Meat Purchase Specifications standards in effect in North America.
It is the back portion of pork loin that is left when the centre loin is removed by a straight cut down in front of the hipbone. A small portion of tenderloin may be included on the bottom.
It has more fat than loin roasts, less fat than shoulder roasts. It also has some bones in it, so it can be a bit trickier to carve.
It is a very inexpensive cut of pork.