A file that contains more than plain text (i.e. photos, sounds, a spreadsheet, or a formatted word-processing document). In contrast to ASCII files, which contain only characters (plain text), binary files contain additional code information. A binary file is made up of machine-readable symbols that represent 1s and 0s. Binary files include sound files, graphics files, and software, and are frequently called binaries.

This all becomes important when you wish to transmit a file over the Internet. Let's say you want to download a neat piece of software called "Fitware" to help you keep track of your fitness regime. Depending on the software you use, you may find yourself confronted with a choice of file formats to download. If the file is a piece of software (like the "Fitware" program), a sound file, or a picture file, you will choose the "binary" option.