Back bacon is a traditional British cut of bacon sliced to include one piece of pork loin and one piece of pork belly combined into the same cut. The name refers to the cut of meat, which includes meat from the loin (or back), and distinguishes it from other bacon made from exclusively pork belly or other cuts. Like other bacon, back bacon can be brined, cured, boiled, or smoked. It is much leaner than American style bacon made only from the belly.
Bacon made only from the loin is sold as "Canadian Bacon" or "Canadian-Style Bacon" in the United States. It does not include the belly at all, and is sold as lean medallions that are reminiscent of sliced ham Canadian-style bacon is cut from the lean eye of the loin, which is taken from the middle of back. It is fully cooked and it is usually smoked. In the early 20th century the British began importing "side bacon" from Canada due to a pork shortage. This product, which was smoked, was referred to as "Wiltshire Sides". The ensuing popularity of this "Canadian" bacon style led to the introduction in the United States of the smoked preparation known as Canadian-style bacon today.