What is both "off-site" and "synchronous" is the "remote class".
A example of what is both "off-site" and "asynchronous" is:
"Virtual schools" on WWW, where classrooms, laboratory, library, forum, and anything you can imagine can be set.
Note that being absent of real humanbeings in the scene does not mean lacking of interactivity/engagement. The realization of the interactivity/engagement depends on your design.
The "information database service" can be considered as a kind of "offsite education", if in a broad sense.