Final answer:
The crows feet notation in an ERD represents a cardinality constraint, which indicates the minimum and maximum number of occurrences of entities in a relationship, commonly one-to-many or many-to-many.
Step-by-step explanation:
The crows feet notation on an Entity-Relationship Diagram (ERD) is a type of cardinality constraint. Cardinality specifies the numerical attributes of the relationship between two entities by expressing the minimum and maximum number of entity occurrences associated with one occurrence of the related entity. For instance, in a 'one-to-many' relation, one entity occurrence links to potentially many occurrences in the related entity. However, if a crow's foot notation is used, it indicates potentially multiple occurrences, most commonly representing a 'many-to-many' or a 'one-to-many' relationship, contingent on its placement in the ERD.