What is Nominated Proof of Stake (NPoS)?

Nominated Proof of Stake (NPoS) is a variation of the Proof-of-Stake (PoS) consensus mechanism employed by the Polkadot blockchain network's main Relay Chain and Polkadot-based parachains (independent blockchains or specialized shards). Instead of using the traditional PoS methodology, NPoS is used to select validators through Polkadot network nominators. Nominators typically only choose validator nodes they trust but they can lose DOT, Polkadot's native cryptocurrency, if they choose malicious validator nodes through a process called slashing.