A schema defines the structure and expected format of data, specifying which fields exist, their types, and how they are related.
In a [[relational database]], the schema includes the table (relation) names, the fields in each, the data type of each field, and the relationships between tables.
A [[JSON]] Schema for a dataset describing public parks might specify that each park has a `name` (string), `location` (coordinates), and `amenities` (list of strings).
An [[RDF]] schema (RDFS) that says: "`ex:Park` is a subclass of `schema:Place`, and it has a property `ex:hasAmenity` with range `ex:Amenity`"