IRC-IT manages a resource collection called Domain, or Windows Domain, or Active Directory Domain, or Microsoft Windows Domain, or...
The primary goals of a domain are:
The name of the Jacobs University domain is "JACOBS".
The domain contains several different domain objects, or domain accounts.
Domain accounts are either JACOBS computer accounts or JACOBS user accounts (plus others).
In addition, there are JACOBS security groups. A security group is a collection of accounts (and other groups).