Ibid. (Latin, short for ibidem, meaning "in the same place") is the term used to provide an endnote or footnote citation or reference for a source that was cited in the preceding endnote or footnote. This is similar in meaning to idem (meaning something that has been mentioned previously; the same), abbreviated Id., which is commonly used in legal citation.1 To find the ibid. source, one must look at the reference preceding it. Ibid. may also be used in the Harvard (name-date) system for in-text references where there has been a close previous citation from the same source material.23 The previous reference should be immediately visible, e.g. within the same paragraph or page. Many academic publishers now prefer that "ibid." should not be given in italics, as it is a commonly found term.4
Notice that ibid. is an abbreviation where the last two letters of the word are not present; thus, it always takes a period (full stop) in both American and British usage.
-  E. Vijh, Latin for Dummies (New York: Academic, 1997), p. 23.
-  Ibid.
-  Ibid., p. 29.
-  Al Azif, The Necronomicon (Petrus de Dacia, 1994).
-  Ibid. 1, p. 34.
Reference 2 is the same as reference 1: E. Vijh, Latin for Dummies on page 23, whereas reference 3 refers to the same work but at a different location, namely page 29. Intervening entries require a reference to the original citation in the form Ibid. <citation #>, as in reference 5.
- Style guide
- Ditto mark
- Ibid: A Life is a novel by Mark Dunn, made up entirely of endnotes.
- List of Latin abbreviations
- List of Latin phrases
- List of legal Latin terms
- Loc. cit.
- MLA style
- Op. cit.
- "Idem". thefreedictionary.com. Retrieved 11 May 2008.
- Chicago Manual of Style Online, (13.64).
- New Hart's Rules, Oxford University Press, 2005, p.396
- Cambridge University Press style sheet, 2013: www.cambridge.org/us/notesforauthors/cambridge_style.doc
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