Question: what is the difference between instance of an entity and entity set?
Answer: An entity is an object that exists and is distinguishable from other objects. For instance, John Harris with S.I.N. 890-12-3456 is an entity, as he can be uniquely identified as one particular person in the universe. ... An entity set is a set of entities of the same type (e.g., all persons having an account at a bank).