Control Plane
In plain terms
The brain of a cluster that makes scheduling and management decisions.
Going deeper
The control plane runs the components (API server, scheduler, controllers) that decide and enforce the cluster's desired state. It directs the worker nodes.
Under the hood
Includes the API server, etcd, scheduler, and controller manager; managed services run it for you.
Examples
Kubernetes masters, API server, scheduler, controllers, managed control planes.
Think of it like...
Like the air-traffic-control tower directing all the planes (workloads).