Hull 101
It is normally the the largest single component of the armored vehicle. There are two types, sponson and box. The sponson type is where the hull protrudes over the running gear like in this picture of the BMP-2.
The box type is where the hull sits between the running gears. Do not let it confuse you if there is fenders over the the tracks as those are not considered part of the hull. Notice this in the picture of the T-62 the fender and overhang are not actually part of the hull.