Attachments are the files associated with a ticket or a comment.

Tickets and contacts can be grouped into Collections. Collection resource usually maps to the various grouping systems used in the underlying product. Some examples are lists, projects, epics, etc. You can differentiate between these grouping systems using the type attribute of a Collection.

Core resource which represents some work that needs to be carried out. Tickets are usually mapped to issues, tasks, work items, etc. depending on the underlying product.

Ticket Priorities represent the intended order in which the Tickets should be worked on. Some products provide customizing the Ticket Priorities.

Users represent the people using the underlying ticketing system. They are usually called agents, team members, admins, etc.

Workspaces represent the top-level subdivision in a ticketing system. They usually have their own set of settings, tickets, statuses, priorities and users. Some of the usual terminologies used by the products for the top-level subdivision are projects, bases, spaces, workspace, etc. A Workspace could belong to an Organization.