A unique name that identifies a file stored on disk. In DOS, a filename is made up of eight characters plus a three-character filename extension which defines the type of file. For example, a letter might be called Letter1.doc. In Windows 95 you can enter long filenames that are not limited to eight characters. You can use most characters in a filename, capitals and lower case. It's also possible to have two or more files with the same filename, as long as they are stored in different directories or folders on a disk.