A note is a string of text placed at the bottom of a page in a book or document or at the end of a chapter, volume or the whole text. The note can provide an author's comments on the main text or citations of a reference work in support of the text.
Footnotes are notes at the foot of the page while endnotes are collected under a separate heading at the end of a chapter, volume, or entire work. Unlike footnotes, endnotes have the advantage of not affecting the layout of the main text, but may cause inconvenience to readers who have to move back and forth between the main text and the endnotes.
In some editions of the Bible, notes are placed in a narrow column in the middle of each page between two columns of biblical text.
In English, a footnote or endnote is normally flagged by a superscripted number immediately following that portion of the text the note references, each such footnote being numbered sequentially. Occasionally a number between brackets or parentheses is used instead, thus: , which can also be superscripted.
Typographical devices such as the asterisk (*) or dagger (†) may also be used to point to notes; the traditional order of these symbols in English is *, †, ‡, §, ‖, ¶. Other symbols, including the #, Δ, ◊, ↓, and ☞, have also been used. In documents like timetables, many different symbols, letters and numbers may refer the reader to particular notes.
In CJK languages, written with Chinese characters, the symbol ※ (called reference mark; Japanese: komejirushi; Korean: chamgopyo) is used for notes and highlighting, analogously to the asterisk in English.
Notes are most often used as an alternative to long explanations, citations, comments or annotations that can be distracting to readers. Most literary style guidelines (including the Modern Language Association and the American Psychological Association) recommend limited use of foot- and endnotes. However, publishers often encourage note references in lieu of parenthetical references. Aside from use as a bibliographic element, notes are used for additional information, qualification or explanation that might be too digressive for the main text. Footnotes are heavily utilized in academic institutions to support claims made in academic essays covering myriad topics.
In particular, footnotes are the normal form of citation in historical journals. This is due, firstly, to the fact that the most important references are often to archive sources or interviews which do not readily fit standard formats, and secondly, to the fact that historians expect to see the exact nature of the evidence which is being used at each stage.
The MLA (Modern Language Association) requires the superscript numbers in the main text to be placed following the punctuation in the phrase or clause the note is in reference to. The exception to this rule occurs when a sentence contains a dash, in which case the superscript would precede it.
Aside from their technical use, authors use notes for a variety of reasons:
Associate Justice Stephen Breyer of the Supreme Court of the United States is famous in the American legal community for his writing style, in which he never uses notes. He prefers to keep all citations within the text (which is permitted in American legal citation). Richard A. Posner has also written against the use of notes in judicial opinions. Bryan A. Garner, however, advocates using notes instead of inline citations.
HTML, the predominant markup language for web pages, has no mechanism for marking up notes. Despite a number of different proposals over the years, and repeated pleas from the user base, the working group has been unable to reach a consensus on it. Because of this, MediaWiki, for example, has had to introduce its own
<ref></ref> tag for citing references in notes, an idea which has since also been implemented for generic use by the Nelson HTML preprocessor.
It might be argued that the hyperlink partially eliminates the need for notes, being the web's way to refer to another document. However, it does not allow citing to offline sources and if the destination of the link changes, the link can become dead or irrelevant. A proposed solution is the use of a digital object identifier.
Early printings of the Douay Bible used two closely spaced colons (actually squared four dot punctuation mark U+2E2C) to indicate a marginal note.
At times, notes have been used for their comical effect, or as a literary device.