Relation or relations may refer to:

General uses

International relations International relations (IR, and also referred to as international studies, international politics, or international affairs) is an academic discipline. In a broader sense, the study of IR, in addition to multilateral relations, concerns al ...

, the study of interconnection of politics, economics, and law on a global level *

Interpersonal relationship In social psychology, an interpersonal relation (or interpersonal relationship) describes a social association, connection, or affiliation between two or more people. It overlaps significantly with the concept of social relations, which a ...

, association or acquaintance between two or more people *

Public relations Public relations (PR) is the practice of managing and disseminating information from an individual or an organization (such as a business, government agency, or a nonprofit organization) to the public in order to influence their perception. Pu ...

, managing the spread of information to the public * Sexual relations, or

human sexual activity Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express Human sexuality, their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., ...

Social relation A social relation is the fundamental unit of analysis within the social sciences, and describes any voluntary or involuntary interpersonal relationship between two or more conspecifics within and/or between groups. The group can be a language or ...

, in social science, any social interaction between two or more individuals

Logic and philosophy

Relation (philosophy) Relations are ways in which several entities stand to each other. They usually connect distinct entities but some associate an entity with itself. The adicity of a relation is the number of entities it connects. The direction of a relation is ...

, links between properties of an object * Relational theory, framework to understand reality or a physical system

Mathematics

A finitary or ''n''-ary relation is a set of ''n''-tuples. Specific types of relations include: *

Relation (mathematics) In mathematics, a relation denotes some kind of ''relationship'' between two mathematical object, objects in a Set (mathematics), set, which may or may not hold. As an example, "''is less than''" is a relation on the set of natural numbers; it ...

(an elementary treatment of binary relations) *

Binary relation In mathematics, a binary relation associates some elements of one Set (mathematics), set called the ''domain'' with some elements of another set called the ''codomain''. Precisely, a binary relation over sets X and Y is a set of ordered pairs ...

(or diadic relation – a more in-depth treatment of binary relations) *

Equivalence relation In mathematics, an equivalence relation is a binary relation that is reflexive, symmetric, and transitive. The equipollence relation between line segments in geometry is a common example of an equivalence relation. A simpler example is equ ...

Homogeneous relation In mathematics, a homogeneous relation (also called endorelation) on a set ''X'' is a binary relation between ''X'' and itself, i.e. it is a subset of the Cartesian product . This is commonly phrased as "a relation on ''X''" or "a (binary) relation ...

Reflexive relation In mathematics, a binary relation R on a set X is reflexive if it relates every element of X to itself. An example of a reflexive relation is the relation " is equal to" on the set of real numbers, since every real number is equal to itself. A ...

Serial relation In set theory a serial relation is a homogeneous relation expressing the connection of an element of a sequence to the following element. The successor function used by Peano to define natural numbers is the prototype for a serial relation. Bertra ...

* Ternary relation (or triadic, 3-adic, 3-ary relation) Relation may also refer to: * Directed relation * Relation algebra, an algebraic structure inspired by algebraic logic

Databases and ontology

Relational model The relational model (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd, where all data are represented in terms of t ...

, an approach to managing data **

Relation (database) In database theory, a relation, as originally defined by E. F. Codd, is a set of tuples (d1,d2,...,dn), where each element dj is a member of Dj, a data domain. Codd's original definition notwithstanding, and contrary to the usual definition in ...

, a component of a relational database **

Relational algebra In database theory, relational algebra is a theory that uses algebraic structures for modeling data and defining queries on it with well founded semantics (computer science), semantics. The theory was introduced by Edgar F. Codd. The main applica ...

Relational calculus The relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that is part of the relational model for databases and provide a declarative way to specify database queries. The raison d'être ...

Relational database A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A Relational Database Management System (RDBMS) is a type of database management system that stores data in a structured for ...

, a digital database * Relationships (also known as relations), one of the

ontology components Contemporary Ontology (information science), ontologies share many structural similarities, regardless of the ontology language in which they are expressed. Most ontologies describe individuals (instances), classes (concepts), attributes, and rel ...

Art and literature

* '' Relation aller Fürnemmen und gedenckwürdigen Historien'', the first newspaper * ''Relation'' (film), a 1982 Japanese experimental short film by Toshio Matsumoto * ''Relations'' (album), a 2004 album of cover versions by Kathryn Williams

Linguistics

* Grammatical relation, a functional relationship between constituents in a