It is a variant of the Proof of Stake consensus mechanism. Blockchains using Delegated Proof of Stake do not choose block validators from the totality of users with staked tokens but from a fixed number of delegates elected by network participants. Those with staked tokens can transfer their right to be chosen as validators to delegates. In this way, the network participants vote for the most efficient delegates and relieve the negligent ones from their duties. In return for supporting the delegates, the network participants receive block reward in proportion to the size of the stake they have delegated.
Delegated Proof-of-Stake is considered one of the most democratic consensus mechanisms because all token holders have the opportunity to participate in block creation and receive rewards, not just large holders.