A punch card is a piece of stiff paper that contains holes punched in specific patterns to represent data. Traditionally used in early computing and data processing, these cards allowed machines to read and interpret information. Each hole corresponds to a specific value or instruction, enabling the storage and retrieval of data in a physical format. Originally popularized in the late 19th century, punch cards were widely used in various industries, including manufacturing and accounting. They played a crucial role in the development of early computers, such as those designed by Herman Hollerith, who created the first successful punch card system for the 1890 U.S. Census.