(computing, programming) In functional programming, a kind of higher-order function that is the opposite of a fold.

(transitive) To undo a folding.

(intransitive) To become unfolded.

(intransitive) To turn out; to happen; to develop.

(transitive) To lay open to view or contemplation; to bring out in all the details, or by successive development; to reveal.

(transitive) To release from a fold or pen.