Address BookA directory of address lists available to Exchange users that enables them to address e-mail messages, and select conferencing resources.
address listA collection of recipient and other Active Directory objects. Each address list can contain one or more types of objects (for example, users, contacts…
address spaceAddress information that identifies a message and its route. [Exchange 5.5]
Administrator programA graphical user interface that enables administrators to manage and configure Exchange objects, such as organizations, sites, and servers. [Exchange 5.5]
advanced securityProvides administrators and users with the ability to protect and verify messages. [Exchange 5.5]