(1) As a noun, the format is the structure, or layout, of an item.

Screen formats are the layout of windows and data on the screen.

Report formats are the columns, headers and footers on a page.

Record formats are the fields within a record.

File formats are the structure of program and data files. Each has its own headers, codes and rules for laying out the content. There are many different file structures for each kind of file, including executable programs, word processing documents, graphics files and databases. See graphics formats, extension, header, disk format and style sheet.

(2) As a verb, to initialize a storage medium (hard disk, CD-RW, etc.) to hold data. See format program.