/mes-dos/ (Or MS-DOG, Messy-DOS, mess-dross, mess-loss, mush-dos) Derisory term for MS-DOS. Often followed by the ritual banishing "Just say No!" Most hackers (even many MS-DOS hackers) loathe MS-DOS for its single-tasking nature, its limits on application size, its nasty primitive interface, and its ties to IBMness (see fear and loathing). In Ireland and the UK it is sometimes called "Domestos" after a brand of toilet cleanser.