Side Snippet - Territory and related entities.

Field services uses territories to relate 'Postal Codes' to.

Recall in  Dynamics CRM 'Territories' is a geographical area that is usually assigned to a salesperson.
As per the documentation:

Territories are used to divide large service areas. If a service territory is assigned to a service account record, and a work order is generated for that service account, then the work order will inherit the service territory from the service account.


Recall 'Business Units' are part of the security model.
As per the documentation:

An organization in Microsoft Dynamics 365, such as a holding company or a corporation, is made up of business units. A business unit is a unit of the top-level organization. Business units can be parents of other business units (child business units). The first business unit created for an organization is called the root business unit.


Recall the 'Site' entity represents a location or branch office where an organization does business. As per the documentation:

Sites enable resources, services, and appointments to be defined at a particular location with an associated time zone. Location, correct selection of resources, and time zone are important elements in the scheduling of service appointments when multiple locations of doing business are involved. You can use sites to limit what resources, such as users and equipment, can be scheduled for a specific service activity.

Note: 'Sales Territory' and 'Service Territory' utilise the same underlying enatity 'Territory'.