Modular design, or “modularity in design”, is an approach (design and otherwise) that subdivides a system into smaller parts called modules or skids, that can be independently created and then used in different systems. A modular system can be characterized by functional partitioning into discrete scalable, reusable modules; rigorous use of well-defined modular interfaces; and making use of industry standards for interfaces.

Modularity offers benefits such as reduction in cost (due to less customization), shorter learning time, flexibility in design, augmentation (adding new solution by merely plugging in a new module), and exclusion.