Entity means anything with distinct and independent existence.
Entity type is basically a collection of entities that have the similar attributes.
Entity set is the collection as a set of all entities of the similar type.
So, Entity type and entity set are analogous.
Example of entity set: set of all persons, universities, companies
An entity is represented by a set of attributes, that is descriptive properties possessed by all members of an entity set.
Example: student = (student-id, student-name, address-street, address-city), item = (item-number, price)
