Core Concepts - Sandeep-K-Khandelwal/CKAD GitHub Wiki
Definitions
Node - A node is a machine – physical or virtual – on which Kubernetes is installed
Worker node (Minions) - A node is a worker node where containers are hosted.
Cluster - A cluster is a set of nodes grouped together. This way even if one node fails you have your application still accessible from the other nodes. Moreover having multiple nodes helps in sharing the load as well.
Master node - The master is another node with Kubernetes installed in it, and is configured as a Master. The master watches over the nodes in the cluster and is responsible for the actual orchestration of containers on the worker nodes.