Domain-driven design is a design approach that attempts to match the mental model of the problem being addressed. In particular, there are three main goals with DDD:
- Discover domain model by agreeing to common set of terms, processes, actors, and other phenomenon
- Take those terms and embed them in code to create a rich domain model that reflects the actual business and its rules
- Protect that domain model from other technical intricacies
https://khalilstemmler.com/articles/domain-driven-design-intro/
Domain is a fancy way of describing the problem we are solving, while the model is a map of a process or phenomenon that captures a useful property.