For referencing in Wikipedia, see Wikipedia:Citing sources.

In general, a reference is something that refers to or designates something else, or acts as a connection or a link between two things. The objects it links may be concrete, such as books or locations, or abstract, such as data, thoughts, or memories. The object which is named by a reference, or to which the reference points, is the referent.

The term reference is used with different specialized meanings in a variety of fields, as follows:

Semantics

In semantics, reference is generally construed as the relation between nouns or pronouns and objects that are named by them. Hence the word "John" refers to John; the word "it" refers to some previously specified object. The objects referred to are called the "referents" of the word. Sometimes the word-object relation is called denotation; the word denotes the object. The converse relation, i.e. object-word, is called exemplification; the object exemplifies what the word denotes.

Reference and Meaning

As Frege discovered, reference cannot be treated as identical with meaning: "Hesperos" (an ancient Greek name for the evening star) and "Phosphorus" (an ancient Greek name for the morning star) both refer to Venus, but the astronomical fact that '"Hesperos" is "Phosphorus"' can still be informative, even if the 'meanings' of both "Hesperos" and "Phosphorus" are already known. This problem led Frege to distinguish between the sense of a word and its reference.

Absent Referent

Main article: Absent referent

Words can often be meaningful without having a referent. Fictional and mythological names such as "Bo-Peep" and "Hercules" show that this is possible.

The sign "God" can be considered to have an absent referent, because God cannot be experienced directly. Additionally, certain sects of Judaism and other religions consider it sinful to write, discard or deface the name of the divine. To avoid this problem, the signifier G-d is sometimes used, which is a sign with referes to another sign with an absent referent.

In Mathematics, the absent referent can be seen with the symbol for zero, "0" or the empty set, "{ }".

The absent referent was written about by vegan feminist Carol Adams to explain a psycho-social detachment which occurs in people who eat meat between the consumer and the Other. There is an implicit presumption that if people had a connection to the animal which was the source of the food, or the violence involved in the slaughter, much less meat eating would occur.

Linguistic Sign

The semantic sign can be considered a subset of a more general concept, the linguistic sign, first elucidated by Ferdinand de Saussure‎. A sign contains two parts, the signified (a thought which represents an object), and the signifier (the sound or written word). Both have a referent (the actual physical object).

Art

In Art, a reference is an item from which a work is based. This may include an existing artwork, a reproduced (i.e. photo) or directly observed (i.e. person) object, or the artist's memory.

Computer science

Main article: reference (computer science)

In computer science, references are datatypes which refer to an object elsewhere in memory, and are used to construct a wide variety of data structures such as linked lists. Most programming languages support some form of reference.

The C++ programming language has a specific type of reference also referred to as a reference; see reference (C++).

Geometry

A reference point is a location used to describe another one, by giving the relative position. Similarly we have the concept of frame of reference (both in physics and figuratively), benchmark (in surveying and figuratively), etc.

Libraries

In a library, the word reference may refer to a dictionary, encyclopedia, or other reference work that contains many brief articles that cover a broad scope of knowledge in one book, or a set of books. However, the word reference is also used to mean a book that cannot be taken from the room, or from the building. Many of the books in the reference department of a library are reference works, but some are books that are simply too large or valuable to loan out. Conversely, selected reference works may be shelved with other circulating books, and may be loaned out.

References to any type of printed matter come in electronic or at least machine-readable form nowadays. For books there exists the ISBN, for journal articles, the digital object identifier (DOI) is gaining relevance. Printed information on the Internet is usually referred to by some kind of uniform resource identifier (URI).

Scholarship

In scholarship, a reference may be a citation of a text that has been used in the creation of a piece of work such as an essay, report, or oration. Its primary purpose is to allow people who read such work to examine the author's sources, either for validity, or simply to learn more about the subject. Such items are often listed at the end of an article or book in a section marked Bibliography or in a section marked References. A Bibliography section will often contain work not cited by the author, but used as background reading or listed as potentially useful to the reader. A section labelled References should contain all and only work cited in the main text. In some circles the latter is known as the EC250 Rule.

Copying of material by another author without proper citation or without required permissions amounts to 'plagiarism'.

Personal references

In the labour market, a reference is a letter to a prospective employer regarding a job applicant's characteristics. Usually the person providing the reference - the referee - is a previous boss, or someone of some distinction in government, the clergy, or education, who can personally vouch for the applicant's employability; see also credit reference.

Canadian law

Main article: reference question

A Reference question, or "Reference" is a procedure through which the government of Canada can submit legal questions to the Supreme Court of Canada and provincial governments to the provincial courts of appeal.

See also

Look up reference in
Wiktionary, the free dictionary.

• Library reference desk
• List of reference tables
• Reference work
• Self-reference
• Antecedent (grammar)
• Exemplification