What is the difference between a Theater and an Audio Zone?

Theaters are multi-channel systems, they can range from as few as 2 channels and up 32 channels (depending on your ISP's options) with subwoofers.

Audio Zones are mono or stereo audio/video systems, occupying 1 or 2 channels. Audio zones are independent from theaters and can be played at the same time, using either the same or a different input source than the Theater.