A reference, or a references point, is the intensional use of one thing, a point of reference or reference state, to indicate something else. When reference is intended, what the reference points to is called the referent.

Some general examples are:

• the name Jane Doe used to identify a particular woman;
• a traffic sign warning of an upcoming turn-off;
• a wedding ring indicating a certain kind of relationship; and
• samples of various musical works being incorporated into a new one.

References may be indicated by sounds (like name), pictures (like roadsigns), text (like bibliographies), indexes (like numbers) and objects (like rings); but a range of other concrete or abstract methods can be used. This included methods that deliberately hide the reference from some observers, as in cryptography.

The following sections give specific usages of reference in different subjects.

Academics and scholarship

In academics and scholarship, an author-title-date information in bibliographies and footnotes, specifying complete works of other people. Copying of material by another author without proper citation or without required permissions is plagiarism.

Keeping a diary allows an individual to use references for personal organization, whether or not anyone else understands the systems of reference used. However, scholars have studied methods of reference because of their key role in communication and co-operation between different people, and also because of misunderstandings that can arise. Modern academic study of reference has been developing since the 19th Century.