“Op. cit.” is a shortened form of the Latin term “opere citato”, which means “in the work already cited” in English. It is commonly used in academic and scholarly writing to refer to a source that has already been cited in the same document. When you use “op. cit.”, you are indicating that the source you are citing can be found in the same work or reference as a previously mentioned citation. However, you are not providing the full citation details again. Instead, readers are expected to refer back to the earlier citation for complete information about the source.