Codabar is a linear barcode symbology. It and its variants are also known as Codeabar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995 or USD-4. It was designed to be accurately read even when printed on dot-matrix printers for multi-part forms such as FedEx air bills and blood bank forms, where variants are still in use as of 2007.