Final answer:
In database systems, entities are related through associations, which can be regular or weak depending on whether they connect to an owner or other entity sets. Regular associations are denoted by a single outline, while weak ones are double-outlined.
Step-by-step explanation:
Relationships in database theory relate two or more entities with specific meaning. The participants in these relationships are entities in the relationship. There are two kinds of relationships that can be identified: regular and weak. Regular relationships connect strong or weak entity sets (with the exception of the owner) and are usually represented with a single outline, whereas weak relationships connect a weak entity set to its owner and are represented with a double outline. The choices given (Associations, Connections, Dependencies, and Linkages) all are terms that can be used to describe these relationships. However, in the context of database systems and entity-relationship models, the most appropriate term for these relationships would be Associations, which describe how entities interact with each other within a system.