Entities are references to isotopes, food, libraries, stars and hundreds of other types of things in the world. With entities, you can retrieve data like the length and an image of a zebra; implicit entity classes allow querying for entities using constraints on property values. Entity stores allow you to register your own entities. Version 12 of the Wolfram Language extends the capabilities of the entity framework by adding support for "on the fly" properties, filtering and sorting entities by general conditions, aggregation, combining types and sampling of entity classes.