What is delegating?

Some articles on delegating:

Prefix Delegation
... This is one of the methods for delegating IPv6 address prefixes to an IPv6 subscriber's network (or "site") ... mechanism is intended for simple delegation of prefixes from a delegating router to requesting routers ... It is appropriate for situations in which the delegating router does not have knowledge about the topology of the networks to which the requesting router is attached, and the delegating router does not require ...