From Longman Dictionary of Contemporary EnglishDOSDOS /dɒs $ dɑːs/ noun [uncountable] technical TD (Disk Operating System) software that is loaded onto a computer system to make all the different parts work together
Examples from the Corpus
DOS• You can do this in Word or in DOS.• In DOS and Windows 3. 1, you have to set up the modem manually for each program.• Prices include DOS 5, a SuperVGA monitor and Windows 3.1.• I've deleted everything and re-installed DOS 5 and Windows 3.1 from scratch, all to no avail.• This isn't as easy as it sounds because all the DOS 5 files are compressed.• Printer number 6 is the DOS Text Printer.• Pressing the Y key at this stage will return you to DOS.• For instance, as with DOS, the names of Windows documents were limited to eight characters.From Longman Business DictionaryDOSDOS /dɒsdɑːs/ noun [uncountable]COMPUTING Disk Operating System; computer software that controls and manages the different operations done by a computer, especially storing and finding informationThe package will run on Unix, DOS and Novell networks. 