A footnote is a note placed at the bottom of a page of a book or document that comments on, and may cite a reference for, a part of the main text and is normally flagged by a superscript number within the main text thus:

¹ for the first footnote on the page, ² for the second footnote, and so on.

A footnote reference symbol should be placed at the end of the section in question (within the main text) as opposed to before it.

Occasionally a number between brackets or parentheses, is used instead, thus: [1]. Typographical devices such as the asterisk (*) or dagger (†) may also be used to point to footnotes. In documents like timetables many different symbols, as well as letters and numbers, may be used to refer the reader to particular footnotes.

Sometimes, especially in learned works, what are loosely called "footnotes" do not in fact appear at the foot of the particular page where the text to which they apply is printed, but are collected together, usually chapter by chapter, and appear as an appendix of notes at the end of the work. Such footnotes are more accurately called endnotes.

• The U.S. Government Printing Office Style Manual devotes six pages to the topic.
• NASA has guidance for footnote usage in its historical documents.^{A Guide to Footnotes and Endnotes for NASA History Authors." NASA History Style Guide. Accessed on March 24, 2005.}

See also

• Wikipedia:Footnotes
• Wikipedia:Footnote2
• Wikipedia:Footnote3
• Wikipedia:Footnote4
• Wikipedia:References
• Wikipedia:Verifiability
• Wikipedia:Cite sources