Other listings of the contents of magazines and journals, especially for older materials, are called periodical indexes. An index is a topical listing of the contents of an identified body of information. For example, the index to a book identifies page(s) on which a particular name or subject appears in the book. A periodical index is a subject listing (often including lists for authors and titles as well as subject words) of the articles from a selected group of periodicals.
Periodical is a term used for publications which come out "periodically," on a predictable basis. Generally they are purchased on a subscription basis and they include newspapers, magazines and journals.