I see no mention of MIMO on their website, but ...
MIMO only implies multiple antenna at each end, allowing multiple data streams to be used in parallel. The multiple antenna are often designed into a single enclosure.
802.11 ac equipment is designed for MIMO work, so it wouldn't surprise me if they were talking about a point-to-multipoint wireless design.
Something like this at the mast:
Something like this at the house:
All capable of being used in both the licenced and unlicenced parts of the 5GHz spectrum.
Some other useful links can be found in this old thread: