Why aren't signals simply called events?
Signals typically have an association with an operating system facility and events are typically application-defined.  In some technology stacks, the OS-level stuff may be hidden well enough that there isn't a difference in the API, but in others perhaps not.
From what I can tell, in Python and and Django, signals are simply delegated events.  Is there anything that functionally differentiates them from the typical notion of events in C#, Java, ActionScript, etc?