Index card

An index card, called a record card in British English and a system card in Australian English, consists of card stock (heavy paper) cut to a standard size, used for recording and storing small amounts of discrete data. A collection of such cards either serves as, or aids the creation of, an index for expedited lookup of information (such as a library catalog or a back-of-the-book index). This system is said to have been invented by Carl Linnaeus, around 1760.

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