with reference to a person ˈīˌdem or ˈēˌdem, with reference to a thing ˈīˌdem or ˈiˌdem, the masculine Latin form having a long i & the neuter form a short i pronoun
Etymology: Latin, same — more at identity
: something previously mentioned : same — used chiefly in bibliographies to avoid repetition of author's name and title when a reference to an item immediately follows another to the same item
idem page 30
— abbr. id.