The Entity Component System (ECS) is an architectural pattern used in software development, particularly in game development, to manage complex, dynamic systems by decoupling data from behavior. By separating entities (objects) into components (data) and systems (logic), ECS enables efficient, scalable, and flexible coding, making it a valuable tool for startups building high-performance applications, such as games, simulations, and interactive experiences, allowing them to optimize resources and improve maintainability.