An engine cylinder block, often referred to "cylinder block" or "engine block," is a crucial component of an internal combustion engine. It serves as the main structural foundation, housing the cylinders where the pistons move up and down.

The cylinder block is typically made of cast iron or aluminum, providing a sturdy and heat-resistant structure. It contains several important features, such as cylinder bores (the hollow spaces where the pistons operate), coolant passages for circulating engine coolant, and oil galleries for lubricating the moving parts.

In a multi-cylinder engine, the cylinder block houses multiple cylinders arranged in a specific configuration, such as inline, V-shape, or horizontally opposed. Each cylinder operates as a separate combustion chamber, allowing the engine to convert fuel into mechanical energy through the movement of pistons.