‘Ibidem’ means ‘in the same place.’ It is used in footnotes to show that information taken from the source cited is the same as the preceding one. It is commonly abbreviated to just ‘ibid.’
‘Ibidem’ is made up of two Latin words. ‘Ibi’ means ‘in that place’ and ‘idem’ means ‘the same.’ It is believed to have first been used in the English language in the late 17th century.
‘Ibid’ is not to be confused with its ‘cousin’ ‘op cit.’ It is only to be used when the preceding footnote cites the same source as the current. Rather than type out that lengthy, boring title, complete with date of publication and publisher, all over again, a simple ‘ibid’ will save you plenty of time.
‘Ibidem’ is usually abbreviated to simply ‘ibid.’ The full-stop is important to highlight the abbreviation. Examples of use are as follows:
“E.B. White – Charlotte’s Web, New York:Harper and Brothers, 1952, p.48
“Vladimir Nabokov – Lolita, London:Penguin Classics, 2000, p.192