Modular design is a research concept and methodological approach focused on decomposing complex systems, products, or processes into smaller, self-contained, and independent units called modules. These modules possess standardized interfaces, enabling their combination, reconfiguration, or replacement to achieve varying functionalities or facilitate system modification and maintenance. The field investigates principles for effective system partitioning, interface definition, and module interaction, emphasizing characteristics such as interchangeability, reusability, and scalability. Its significance lies in enhancing flexibility, reducing complexity, improving development and maintenance efficiency, and enabling adaptation to changing requirements or environments across diverse domains.