A Hangout is a web-based tool created by Google for communicating through video. Up to ten people can “hang out” at one time in a virtual “room.” A Hangout can be as simple or as complex as needed for the task at hand. It can be used simply to converse or, through the use of extra apps and add-ons that Google provides, a Hangout can become a robust, virtual meeting space.
http://www.edutopia.org/blog/educators-schools-google-hangouts-mary-beth-hertz