Note: This term is specific to CockroachDB, a Distributed SQL database. In other contexts, it may be used differently.
Quorum is the consensus required to commit changes in a distributed database such as CockroachDB. Different types of distributed databases may use different systems for quorum. CockroachDB uses the Raft Consensus Protocol, in which a minimum of two nodes are required to achieve a consensus (i.e. quorum) in a three-node system.