A data steward is a job role that involves planning, implementing and managing the sourcing, use and maintenance of data assets in an organization. Data stewards enable an organization to take control and govern all the types and forms of data and their associated libraries or repositories.
Techopedia explains Data Steward
A data steward is a broad job role that incorporates processes, policies, guidelines and responsibilities for administering organizations' entire data in compliance with business and/or regulatory obligations. A data steward’s responsibility stems from an understanding of the business domain and the interaction of business processes with data entities/elements. A data steward ensures that there are documented procedures and guidelines for data access and use. Data stewards works with data custodians, database/warehouse administrators and other related staff to plan and execute an enterprise-wide data governance, control and compliance policy.