Relation or relations may refer to anything that involves communicating with another person, group, society or country.
- Kinship, relationship by genealogical origin
- Social relations, in social science, social interaction between two or more individuals
- International relations, strategies chosen by a state to safeguard its national interests and achieve its foreign policy objectives
Logic and philosophy
- Relation (philosophy), links between properties of an object
- Finitary relation, term in set theory and logic, for a property that assigns truth values to k-tuples of individuals
- Relation of Ideas, in the Humean sense, is the type of knowledge that can be characterized as arising out of pure conceptual thought and logical operations (in contrast to a Matter of Fact)
- Relational theory, framework to understand reality or a physical system in such a way that the positions and other properties of objects are only meaningful relative to other objects
Computers and technology
- Binary relation, a synonym for dyadic relation and 2-place relationship
- Relational algebra, an offshoot of first-order logic (and of algebra of sets), deals with a set of finitary relations which is closed under certain operators
- Relation (mathematics), a generalization of arithmetic relations, such as "=" and "<", that occur in statements, such as "5 < 6" and "2 + 2 = 4"
- Ternary relation, finitary relation in which the number of places in the relation is three. Ternary relations may also be referred to as 3-adic, 3-ary, 3-dimensional, or 3-place.
- Theory of relations, treats the subject matter of relations in its combinatorial aspect, as distinguished from, though related to, its more properly logical study on one side and its more generally mathematical study on another