A catalogue is a comprehensive list of items, usually arranged systematically. It can be a book, usually illustrated, containing details of items for sale, especially as used by mail-order companies. Catalogues can also be used to list all the books or resources of a library. They are used by companies to list all the products that they offer, including descriptions and prices for each product. Catalogues can be used to keep track of books with botanical titles.

The terms "catalog" and "catalogue" are both acceptable spellings, with "catalog" being more popular in American English and "catalogue" being more common in other parts of the world.