Definition:
The Dynamic Systems Development Method (DSDM) is an agile framework that addresses the entire project lifecycle and its impact on the business. Like the broader agile philosophy, DSDM is an iterative approach to software development, and this framework explicitly states “any project must be aligned to clearly defined strategic goals and focus upon early deliver of real benefits to the business.” The framework is built on four principles: feasibility and business study, functional model and prototype iteration, design and build iteration, and implementation.
Further Reading:
Book: UML Distilled Third Edition by Martin Fowler