To conceal.
To extract a substance from blood, sap, or similar to produce and emit waste for excretion or for the fulfilling of a physiological function.
To exude or yield.
To reveal.
To undo a folding.
To release from a fold or pen.
To turn out; to happen; to develop.
To open (anything covered or closed); to lay open to view or contemplation; to bring out in all the details, or by successive development.
In functional programming, a kind of higher-order function that is the opposite of a fold.