It’s a common language between developers and users.
Introduced in domain-driven design by Eric Evans.
Why
- Preserve domain knowledge.
- Streamline the communication between everyone.
Should consist of business domain-related terms only, no technical jargon. It helps to frame domain experts’ mental models in terms that are easy to understand, instead of teaching them about singletons etc.
Should be precise and consistent. No assumptions should be needed. Each term has one and only one meaning.