To tell in a descriptive way.
To interact.
To respond through reaction.
To have a connection.
To bring into a relation, association, or connection (between one thing and another).
To identify with; to understand.
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.