Catamorphism

In category theory, the concept of catamorphism (from Greek: κατά = downwards or according to; μορφή = form or shape) denotes the unique homomorphism from an initial algebra into some other algebra. The concept has been applied to functional programming as folds.

The dual concept is that of anamorphism. See also Hylomorphism (computer science)

Read more about Catamorphism:  Catamorphisms in Functional Programming, Catamorphisms in Category Theory