Add terms to CAPN glossary

proposals/00_capn-glossary.md

@@ -4,7 +4,7 @@ This document inherits terms from [Cluster API
 Glossary](https://cluster-api.sigs.k8s.io/reference/glossary.html) to support
 definitions for the Cluster API Provider Nested implementation.
 
-[C](#c) | [S](#s)
+[C](#c) | [E](#e) | [N](#n) | [S](#s)
 
 # C
 ---
@@ -14,3 +14,60 @@ definitions for the Cluster API Provider Nested implementation.
 ### CAPN
 
 Cluster API Provider Nested
+
+### Component Controller
+
+Operators that create the NestedControlPlane components, including the NestedEtcd controller, NestedAPIServer controller and NestedControllerManager controller.
+
+### Cluster Admin
+
+Responsible for creating the underlying super cluster, deploying component controllers, and in-charge of creating Nested clusters.
+
+# E
+---
+
+### End User
+
+Represents a nested cluster user. These users have limited access to the super cluster.
+
+# N
+---
+
+### NestedControlPlane(NCP)
+
+The control plane that are hosted on the super cluster.
+
+### NestedEtcd(NEtcd)
+
+The etcd that belongs to the control plane of the nested cluster.
+
+### NestedAPIServer(NKAS)
+
+The kube-apiserver which belongs to the control plane of the nested cluster.
+
+### NestedControllerManager(NKCM)
+
+The kube-control-manager which belongs to the control plane of the nested cluster.
+
+### NCP
+
+The abbreviation of the NestedControlPlane.
+
+### NEtcd
+
+The abbreviation of the NestedEtcd.
+
+### NKAS
+
+The abbreviation of the NestedAPIServer.
+
+### NKCM
+
+The abbreviation of the NestedControllerManager.
+
+# S
+---
+
+### Super Cluster
+
+The underlying cluster that manages the physical nodes, all pods created through the NestedControlPlanes will run on this cluster.