In the Active Roles replication model, the Publisher and its Subscribers are collectively referred to as replication group, with each server in the replication group being referred to as replication partner.
Replication group is comprised of replication partners that include a single Publisher and may include any number of Subscribers. When data in a replication partner’s database changes, replication ensures that the data changes are propagated to the databases maintained by all the other replication partners.
NOTE: In the SQL Server documentation, replication partners are referred to as synchronization partners.
Standalone database server
When initially set up, the Administration Service’s database server is configured as a standalone server that does not belong to any replication group.
Articles and publications
Articles are tables of data, partitions of data, or database objects that are specified for replication. Each publication is a collection of articles from one database. This grouping of multiple articles makes it easier to specify a logically related set of data that is to be replicated together. In the Active Roles replication model, each article is a table of data.
SQL Server Agent
SQL Server Agent hosts and schedules the agents used in replication, and provides a way to run replication agents. SQL Server Agent also controls and monitors several other operations outside of replication, including monitoring the SQL Server Agent service, maintaining error logs, running jobs, and starting other processes.