There are 3 types of security groups in Active Directory and you can look at them from 2 perspectives:
Where can the group be used?
Domain local – local domain only
Global – any domain in forest or trusted forest
Universal – any domain in forest
What can the group contain?
Domain local – Domain local from the same domain, Global or Universal from any domain in the forest, Global groups from a trusted external domain
Global – other Global groups from the same domain
Universal – Users, Computers, Global groups, Universal groups from any domain in the forest