Terminology
The ISDN Diversion supplementary services standards document uses "diversion" as a general term to encompass specific features including "Call Forwarding Busy", "Call Forwarding No Reply" and "Call Deflection".
In common language, the terms "Call forwarding" and "Call diversion" are both used to refer to any feature that allows a call to be routed to a third party, and the terms are generally interchangeable.
Read more about this topic: Call Forwarding