A general term for a relational language or a functional language, as opposed to an imperative language. Imperative (or procedural) languages specify explicit sequences of steps to follow to produce a result, while declarative languages describe relationships between variables in terms of functions or inference rules and the language executor (interpreter or compiler) applies some fixed algorithm to these relations to produce a result. The most common examples of declarative languages are logic programming languages such as Prolog and functional languages like Haskell.

See also production system.