What is masternode?
Masternode is simply a cryptocurrency full node or computer wallet that keeps the full copy of the blockchain in real-time, just like your have Bitcoin full nodes and is always up & running. But masternodes are considerably different in their functionality than normal nodes.
They are different because they perform several other functions apart from just keeping the full blockchain and relaying blocks/transactions as a full node does in Bitcoin/Litcoin.
Some of the special functions that these nodes perform are:
Increasing privacy of transactions
Doing instant transactions
Participating in governance and voting
Enable budgeting and treasury system in cryptos
These masternodes are not standalone but they are always communicating with other such nodes to make a decentralized network and are often referred in short form as MN.
Note: Mostly the masternodes perform the tasks that I have listed above but it can slightly vary from cryptocurrency to cryptocurrency depending upon how masternodes have been implemented. But more or less they perform these functions in a cryptocurrency.
Source:
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