+A **pure function** is a function that, given the same input, will always return the same output and causes no observable [Side effect](/wiki/Side_effect). It performs its work without altering external state, making its behavior predictable and its results easy to test and reason about within [Functional programming](/wiki/Functional_programming) paradigms.
+## See also
+- [Immutability](/wiki/Immutability)
+- [Determinism](/wiki/Determinism)
+- [Referential transparency](/wiki/Referential_transparency)
... 1 more lines