A commonly used term in the automotive industry is "power per litre of displacement," which refers to the amount of horsepower that an engine produces for every litre of its capacity. However, there are a few synonymous terms that are frequently used for this same concept. These include engine specific output, specific power, and power density. All of these terms are used to describe the amount of power that an engine produces in relation to its size. While different terminology is used depending on the context, the underlying meaning is the same: the higher the power per litre of displacement, the more powerful the engine.