Taken from here
Q What are delegates?
A When an object receives a request, the object can either handle the request itself or pass the request on to a second object to do the work. If the object decides to pass the request on, you say that the object has forwarded responsibility for handling the request to the second object.
Or, as an easy pseudo example: something sends a request to object1. object1 then forwards the request and itself to object2 -- the delegate. object2 processes the request and does some work. (note: link above gives good examples)
