No, it's not the title of some horror movie, it's a technique in calculus for taking the volume of a regular irregular shape. A regular irregular shape is a shape that, though it may be irregular, if sliced into tiny sections each of those sections will be a regular two dimensional shape. Using the equation for the shape's profile, you can find the volume of the shape by taking the definite integral of the equation multiplied by dx or dy (depending on what coordinate system you are using to graph the equation for the shape's profile). Examples of these types of shapes would include pyramids and stacks of coins offset so that they do not form a straight cylinder. The equations for volume of basic shapes such as spheres and cubes found in early math textbooks were found by determining their volume by slicing.