Component Entity Systems

Component/Entity Systems are an architectural pattern used mostly in game development. A CES follows the Composition over Inheritance principle to allow for greater flexibility when defining entities (anything that's part of a game's scene: enemies, doors, bullets) by building out of individual parts that can be mixed-and-matched. This eliminates the ambiguity problems of long inheritance chains and promotes clean design. However, CES systems do incur a small cost to performance.

For more information visit official Entity Systems Wiki