What is a service delivered between two business units in the same organization known as?

Strategic service is not a standard ITIL classification for services delivered between internal business units.

Delivered service is not a recognized ITIL term used to distinguish intra-organizational service delivery from external delivery.

ITIL defines an internal service as one delivered between departments or business units that are part of the same organization. Both the service provider and consumer exist within the same organizational boundary, which is the key distinction from an external service delivered to third-party or outside customers.

An external service is one delivered to customers or parties outside the organization, not between internal business units.