There are three commonly known types of nodes in blockchain technology: ordinary node, full node, and masternode.
Ordinary nodes is the fundamental of a cryptocurrency, and its purpose is to prevent double spending and secure the blockchain. Nodes are rewarded by contributing to the creation and blocking of network consensus. In PoW, nodes are miners and in PoS they hide wallets.
The full node contains the copy of the blockchain in real time, while the ordinary node does not contain such a copy. The full node can be connected to over 124 nodes, while the ordinary node can only be connected to 8 nodes.
Masternodes are full nodes with extra abilities, they perform different types of services, such as instant shipping, special shipping, and storing full blockchain where they receive block rewards. Masternodes are full nodes in both PoW and PoS.
In short, a masternode is a server located on a decentralized network, used to complete unique functions that ordinary node cannot.