What is Automated Attendant?

Legal Definition
In telephony, an automated attendant (also auto attendant, auto-attendant, autoattendant or AA, or virtual receptionist) allows callers to be automatically transferred to an extension without the intervention of an operator/receptionist). Many AAs will also offer a simple menu system ("for sales, press 1, for service, press 2," etc.). An auto attendant may also allow a caller to reach a live operator by dialing a number, usually "0". Typically the auto attendant is included in a business's phone system such as a PBX, but some services allow businesses to use an AA without such a system. Modern AA services (which now overlap with more complicated interactive voice response or IVR systems) can route calls to mobile phones, VoIP virtual phones, other AAs/IVRs, or other locations using traditional land-line phones.
-- Wikipedia
Legal Definition
Equipment that uses a computer to answer phones rather than people. A message is played and the menu is used to access the party wanted.