Data Steward
The named individual accountable for the definition, quality and appropriate use of a specific data domain.
Governance programmes fail most often for a mundane reason: no individual is accountable for any particular dataset, so quality problems have no owner and definitional disputes have no arbiter.
The steward is a business role, not a technical one. They own what a term means, what quality level is required, who may access the data and for what purposes, and they resolve disagreements between consuming teams. The technical counterpart — the custodian or data engineer — implements and operates, and conflating the two is the classic mistake: an engineer cannot decide what "active customer" means, and should not be asked to.
Three conditions determine whether the role functions. Authority: the steward must be able to make a decision that binds other teams, or they become a mailbox. Capacity: stewardship added to a full-time job with no time allocated is a title, not a role. And scope: a steward for a coherent domain works, a steward for "customer data across the enterprise" is a governance committee wearing one person's name.
The signal that stewardship is real rather than nominal: when two teams disagree about a definition, there is a person who decides, and the decision is recorded and applied.