A relation is a connection between or among concrete objects, abstract entities, or both.
Relations help us understand how entities stand to one another. A cup can be on a table. A child can be related to a parent. A number can be greater than another number. A belief can conflict with evidence. In each case, the meaning does not come from one thing alone. It comes from the connection between things.
Relations apply to both concrete objects and abstract entities. A concrete object can relate to another concrete object in the material world. A bird is above a tree. A hand holds a stone. These relations map to empirical ideas. Abstract entities can also stand in relation to one another. One idea may imply another. One value may conflict with another. One framework may contain a schema. These relations map to rational ideas.
Relations are also a type of universal. Above, equal to, caused by, and similar to are repeatable patterns. A bird may be above something, but above is a relation that can appear across many things. One argument may support one conclusion, but support is a relation that can appear across many abstract entities.
Relations also help clarify state. A state is the current configuration of an entity’s properties, actions, and relations. A person may be employed by a company, married to a spouse, responsible for a child, or logged into a system. Those relations are part of the person’s current state within a framework. If the relation changes, the state changes. A relation is not merely decoration; it can shape what an entity is, what it can do, and what it means.