The publication database is the database on the Publisher that is the source of data and database objects to be replicated. Each publication database used in replication must be enabled. The database is enabled when a member of the sysadmin fixed server role:
Creates a publication on that database using the New Publication Wizard.
Selects the database in the Publisher Properties dialog box.
Executes sp_replicationdboption and sets the option publish (for snapshot or transactional publications) or merge publish (for merge publications) to True.