To truly understand ham, New York butcher Frank Ottomanelli told us, you have to start at the beginning: the pig. Ham, he explained, comes from the hind leg of the animal, and a whole fresh ham typically weighs between 14 and 20 pounds.
A whole ham can be separated into two smaller parts—a good thing if you're serving fewer people and don't want leftovers. The shank-end ham is cut from the lower leg and tends to have more skin, or "rind"; the plumper and meatier butt-end ham is cut from the upper portion. Often the aitch bone, part of the pelvis, is still attached to the butt-end ham; it can be removed, which makes slicing easier.
But, Ottomanelli noted, a ham is still called a ham even if it's not cured or smoked—many cooks enjoy roasting a fresh, uncured ham.