What is the meaning of Id.?

Abbreviation of idem; used in citations to state that the citation is found in the same work as the one previously cited.

Replaces a repeated word to reduce repetition, such as in dictionaries

Acronym of identity document.

Abbreviation of identification.

Abbreviation of identifier.

the same, similar to the preceding

Sr. (a title used before a father's name when his son is given the same name)

the same as the preceding

Source: wiktionary.org