I am primarily coming at this from a Kubernetes point of view, but worth considering across the Rxn projects and wider Anuket. I also see that LFN are already part of the Inclusive Naming project, so maybe there is already an Anuket-wide thing in place for this?

From an RA2 point of view, to maintain alignment with the Kubernetes glossary and naming conventions, e.g. for "Master":

Legacy term, used as synonym for nodes hosting the control plane.[-]
The term is still being used by some provisioning tools, such as kubeadm, and managed services, to label nodes with kubernetes.io/role and control placement of control plane pods.

and for "Control Plane":

The container orchestration layer that exposes the API and interfaces to define, deploy, and manage the lifecycle of containers.[-]
This layer is composed by many different components, such as (but not restricted to):

etcd
API Server
Scheduler
Controller Manager
Cloud Controller Manager
These components can be run as traditional operating system services (daemons) or as containers. The hosts running these components were historically called masters.

We can update our glossary and use of terms like master in the docs, e.g. ra2.k8s.012 states:

A master node must run at least the following Kubernetes control plane services: kube-apiserver, kube-scheduler and kube-controller-manager.

This could very easily be changed to:

A control plane node must run at least the following Kubernetes services: kube-apiserver, kube-scheduler and kube-controller-manager.