Engine block

In an internal combustion engine, the engine block is the structure that contains the cylinders and other components. The engine block in an early automotive engine consisted of just the cylinder block, to which a separate crankcase was attached. Modern engine blocks typically have the crankcase integrated with the cylinder block as a single component. Engine blocks often also include elements such as coolant passages and oil galleries.

The term "cylinder block" is often used interchangeably with "engine block". However, technically, the block of a modern engine (i.e., multiple cylinders integrated with another component) would be classified as a monobloc.