Ref:Engine

From Dark Omen Wiki

In tne most abstract sense, an engine is a piece of software intended to restrict, narrow or channel a wider set of options into a consistent and more particular result. Engines are thus distinct from API and frameworks, which are generally open-ended. while usually incorporating these.

Engines have different degrees of specificness, and more specific engines are often incorporated together hierarchically to achieve a very particular outcome. For example game engines are systems intended for a rigidly defined behavious and outcome (the game) and usually employ graphics and physics engines that limits and guides the game form.

More specific engines are usually data-driven and operate on external resources. An example would be a 3D world rendering BSP engine (f.i. a Quake renderer).