From Joomla! Documentation
The "Permissions" tab, shown below, lets you specify who can perform each type of action:
The Permissions table contains various columns:
- User Groups. Lists the user groups that are available on your Joomla! site. You can specify permissions for each of these groups by using the dropdown controls in the other columns, which represents actions that can be performed by users.
- Admin. Grants users the right to edit this component's Options.
- Manage. Grants users the right to open this component's main screen ("Manager" screen).
- Create. Create new objects (for example, users, menu items, articles, weblinks, and so on).
- Delete. Delete existing objects.
- Edit. Edit existing objects.
- Edit State. Change object state (Publish, Unpublish, Archive, Check In and Trash).
For each user group / action, possible permission options are:
- .... Represents the "Inherit" option, which means that the permission for this group/action is inherited from the site's Global Configuration.
- Deny. Denies this action for this users group.
- Allow. Allows this action for this users group and for child groups.
For more information, please refer to the ACL Tutorial for Joomla 1.6.