A punched card is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widely used for data processing, automation, and computing. Early applications included controlling weaving looms and recording census data. In the 20th century, they became central to business operations and early computers for input, output, and storage. IBM's 80-column format became a dominant standard, and punched cards were used for decades before being replaced by magnetic storage and terminals. Their influence persists in cultural references, standardized data layouts, and computing conventions such as 80-character line widths.