JSI Tip 6964. Description of the different group scopes that you can use to help secure Microsoft Windows 2000 Active Directory directory service objects.

Microsoft Knowledge Base Article 231273 contains the following summary:

Windows 2000 and later extends the Microsoft Windows NT 4.0 concept of user groups by adding Universal and Distribution groups. In Windows NT 4.0, there are only Global and Local groups, and both are considered Security groups.