DDD is a software development approach that focuses on bringing together business and technical concerns. It emphasizes close collaboration between domain experts and developers to build a domain model. The domain model is an abstract representation of the software's purpose area using a ubiquitous language. This language is derived from the domain experts and unifies their terms with those used by developers. The domain model, code, and ubiquitous language should evolve together through refactoring to ensure the software effectively solves business problems. DDD works well with iterative and agile approaches.

1. DDD (Domain-Driven Design) Flávio Silva