Final answer:
Constraints on the minimum number of entities in a relationship are known as minimum cardinalities, a key concept in database design that governs entity relationships.
Step-by-step explanation:
Constraints on the minimum number of entities in a relationship are called minimum cardinalities. In database design, this concept is crucial for setting up the rules that govern the relationships between different entities in a database. For example, in a one-to-many relationship, the minimum cardinality might dictate that one entity must be associated with at least one other entity, but it can also be linked to many others. Similarly, in a many-to-many relationship, the minimum cardinality will define the least number of associations that entities on either side of the relationship can have with each other.