Facebook Groups are pages that you create within the Facebook
social networking site that are based around a real-life interest or group or to declare an affiliation or association with people and things. With a Facebook Group, you are creating a community of people and friends to promote, share and discuss relevant topics.
See “Social Networking Sites” in Webopedia’s Quick Reference section.
See also “How To Create a Facebook Group” in the Quick Reference section of Webopedia.