Wikipedia
COMMAND.COM
COMMAND.COM is the default operating system shell for DOS operating systems and the default command line interpreter on Windows 95, Windows 98 and Windows ME. It has an additional role as the first program run after boot, hence being responsible for setting up the system by running the AUTOEXEC.BAT configuration file, and being the ancestor of all processes. COMMAND.COM's successor on OS/2 and Windows NT systems is CMD.EXE. COMMAND.COM is also available on IA-32 versions of those systems to provide compatibility when running DOS applications within the NTVDM.
COMMAND.COM is a DOS program. Programs executed by COMMAND.COM are DOS programs that use the MS-DOS API to communicate with the operating system (DOS).