What is Nominator (Polkadot)?

A nominator is a node that is used to secure Polkadot's main Relay Chain by selecting trustworthy validator nodes and staking DOT, Polkadot's native cryptocurrency. In this process nominators algorithmically choose network validators by bonding their DOT assets to produce blocks on the Polkadot network, and in exchange receive a portion of validator node rewards. However, nominators are also susceptible to slashing (losing some of their DOT) if the validator nodes they select behave in a malicious manner.