binary file

Any file that is not plain text. Program (.EXE or .COM), sound, video, and graphics files are all types of binary files. Such files require special treatment for inclusion in e-mail sent across the Internet, which can transmit only ASCII text and imposes a size limit of 64Kb per message. Several programs have been developed to code binary files into ASCII for transmission, splitting them into smaller parts as necessary. The most commonly used such program is UUencode, but there are others including base64 and BinHex. See also MIME.