A Rolodex is a rotating file device used to store business contact information. Its name is a portmanteau word of rolling and index and desk. The Rolodex holds specially shaped index cards; the user writes or types the contact information for one person or company onto each card. The cards are notched to be able to be snapped in and out of the rotating spindle. Some users tape the contact's business card directly to the Rolodex index card, or a plastic or vinyl sleeve in the shape of a Rolodex card to place the business card within. Some companies produced business cards in the shape of Rolodex cards, as a marketing idea.
The Rolodex was invented in 1956, by the Danish engineer Hildaur Neilsen, the chief engineer of Arnold Neustadter's company Zephyr American, a stationery manufacturer in New York. First marketed in 1958, it was an improvement to an earlier design called the Wheeldex. Zephyr American also invented, manufactured and sold the Autodex, a spring-operated phone directory that automatically opened to the selected letter, Swivodex, an inkwell that did not spill, Punchodex, a paper hole puncher, and Clipodex, an office aid that attached to a stenographer's knee.