Characteristic

A characteristic entity represents a group of attributes that occur multiple times for an entity, and is not directly identified by any other entity. In the example, HOBBY is a characteristic of PERSON.

Associative or Designative

Associative and designative entities record multiple relationships between two or more entities. If the entity carries only the relationship information, it is termed a designative entity. If it also carries attributes that further describe the relationship, it is called an associative entity. In the example, ADDRESS-USAGE is an associative or designative entity.

Subtype

Subtype entities are the dependent entities in a subtype relationship. In the example, CHECKING‑ACCOUNT, SAVINGS-ACCOUNT, and LOAN‑ACCOUNT are subtype entities.