= Terminology

Web Portal (Portal)::
This is the aggregated view and entry point for the user.
It provides the mechanisms for the multi-tenant, multi-service-provider self-service portal.

Control Plane (CP)::
This runs Crossplane and the AppCat Control Plane (Kubernetes API) which manages all the service instances on worker clusters.
Each zone of a Service Provider runs at least one CP.

Worker Cluster::
Clusters running the actual workload, managed by the Control Plane.
Each zone of a CSP runs at least one Worker Cluster.
Services are directly exposed to the end-user.

Service::
A generic service like "PostgreSQL" or "Keycloak".
This doesn't include pricing or any other aspect of a managed service.

Plan::
A bundle of a service, a price, an SLA and other parameters to form an offering.
It can be instantiated (ordered) and parametrized according to the specification in the offering.

Crossplane specific terms::
* Compositions - A template to define how to create resources.
* Composite Resource Definition (`XRD`) - A custom API specification.
* Composite Resource (`XR`) - Created by using the custom API defined in a Composite Resource Definition. XRs use the Composition template to create new managed resources.
* Claims (`XRC`) - Like a Composite Resource, but with namespace scoping.
* Managed Resource (`MR`) - Represents an external service in a Provider.
* Providers enable Crossplane to provision infrastructure on an external service. Providers create new Kubernetes APIs and map them to external APIs.