A card catalogue is a system of organizing and indexing information on cards or paper slips in a library. Alternative synonyms for this term include a card index, a card catalog, or a bibliographic index. In modern times, digital versions of card catalogues have replaced physical collections in most libraries. Other terms used to describe these electronic databases include digital catalogues, online bibliographies, or virtual libraries. With the rise of online platforms, librarians and archivists have been able to make their collections available to a greater audience and improve accessibility through keyword and title searches. Nonetheless, card catalogues remain an important part of the history of library science.