Final answer:
A Data Flow Diagram (DFD) is used to illustrate the flow of data through a system, showing how data is inputted, processed, stored, and outputted. An example is a DFD for a library management system with entities like 'Librarian' and 'Member', processes such as 'Issue Book', and data stores like 'Book Records'.
Step-by-step explanation:
A Data Flow Diagram (DFD) is a graphical representation used to depict the flow of data through a system. It shows how input data is processed and what the system produces as output. Typically, a DFD illustrates the movement of data between external entities and processes and data stores within a system. For example, consider a simple DFD for a library management system. In this DFD, there might be entities such as 'Librarian', 'Member', and 'Supplier'. Processes could include 'Issue Book', 'Return Book', and 'Order New Book'. Data stores might be 'Book Records', 'Member Records', and 'Supplier Records'.
The DFD would show these entities, processes, and data stores, along with data flows connecting them, indicating how information such as 'Book Availability' or 'Member Details' moves through the system. Using DFDs is a part of the engineering design process, which can also be seen in contexts such as the development of a budget for product development or when creating drawings used to design a product.