Ibid.
Also called: ibidem
A note-style abbreviation meaning “in the same place”, used to repeat the source cited in the immediately preceding note.
Ibid. is short for ibidem, “in the same place”. In a footnote system it saves you retyping a citation you gave one note earlier: note 12 gives the full reference, note 13 reads “Ibid., 47.”
Modern practice has moved against it. Chicago's 17th edition explicitly prefers a shortened note — author surname, short title, page — because ibid. breaks the moment an editor inserts a note between the two, and because it is unhelpful to a reader landing mid-chapter. It also fails outright when the previous note cited more than one work.
Ibid. never appears in author–date or numeric styles. Repeating (Larsen, 2024) or [4] costs nothing, so there is nothing to abbreviate.