Final answer:
An Entity-Relationship Diagram (ERD) is used in the design of a Relational Database and it helps in organizing the structure of the data in a visual format for better understanding and efficiency.
Step-by-step explanation:
An Entity-Relationship Diagram (ERD) is a graphical representation used to conceptualize and model the structure of data within a Relational Database. It is a crucial tool used in database design to illustrate the entities (tables) and their relationships to one another, often used by database designers and developers to lay out the initial structure of the database before it is created. In an ERD, entities are represented by rectangles, and the relationships between them are represented by lines that connect these rectangles. Attributes of each entity are listed within the entity's rectangle. This modeling technique helps ensure that the relational database will be well-organized and efficient for storing, retrieving, and managing the data.