21-letter words containing m, o, i, r
- ventriloquist's dummy — a puppet which is operated by a ventriloquist and made to appear to talk
- virtual memory system — (operating system) (VMS) DEC's proprietary operating system originally produced for its VAX minicomputer. VMS V1 was released in August 1978. VMS was renamed "OpenVMS" around version 5.5. The first version of VMS on DEC Alpha was known as OpenVMS for AXP V1.0, and the correct way to refer to the operating system now is OpenVMS for VAX or OpenVMS for Alpha. The renaming also signified the fact that the X/Open consortium had certified OpenVMS as having a high support for POSIX standards. VMS is one of the most secure operating systems on the market (making it popular in financial institutions). It currently (October 1997) has the best clustering capability (both number and distance) and is very scalable with binaries portable from small desktop workstations up to huge mainframes. Many Unix fans generously concede that VMS would probably be the hacker's favourite commercial OS if Unix didn't exist; though true, this makes VMS fans furious.
- vladivostok agreement — a preliminary arms control accord concluded by Soviet leader Leonid Brezhnev and U.S. President Gerald Ford in Vladivostok, U.S.S.R., in December 1974.
- volumetric efficiency — the ratio of fluid delivered by a piston or ram pump per stroke to the displacement volume of the piston or ram
- volunteers of america — a religious reform and relief organization, similar to the Salvation Army, founded in New York City in 1896 by Ballington Booth, son of William Booth, the founder of the Salvation Army. Abbreviation: VOA.
- warm silence software — A small company run by(?) Robin Watts, producing software for the Acorn Archimedes.
- weinberg-salam theory — electroweak theory.
- well-ordering theorem — the theorem of set theory that every set can be made a well-ordered set.
- what price something? — what are the chances of something happening now?
- william of malmesbury — William of, William of Malmesbury.
- william the conqueror — ("the Conqueror") 1027–87, duke of Normandy 1035–87; king of England 1066–87 (son of Robert I, duke of Normandy).
- wilson's storm petrel — a small petrel, Oceanites oceanicus, that breeds in the Southern Hemisphere but ranges into the North Atlantic and Pacific oceans.
- workers' compensation — a government-sponsored insurance system, funded by contributions from employers, for compensating employees for injury or occupational disease suffered in connection with their employment
- worth someone's while — worth someone's time, consideration, etc.; profitable in some way
- xeroderma pigmentosum — a rare inherited disease characterized by sensitivity to ultraviolet light, exposure resulting in lesions and tumors of the skin and eyes.
- xilinx netlist format — (language, electronics) (XNF) A Hardware Description Language for electronic circuit design, developed by Xilinx, Inc..
- yellow mercuric oxide — a slightly crystalline, water-soluble, poisonous compound, HgO, occurring as a coarse, orange-red powder (red mercuric oxide) or as a fine, orange-yellow powder (yellow mercuric oxide) used chiefly as a pigment in paints and as an antiseptic in pharmaceuticals.
- yellow-fever mosquito — a mosquito, Aedes aegypti, that transmits yellow fever and dengue.
- your mileage may vary — (jargon) (YMMV) The disclaimer American car manufacturers attached to EPA mileage ratings. A humourous way of saying that the thing under discussion will not necessarily give you the same results as the author. Often used to convey the hardware dependence of Unix freeware distributions.
- youth training scheme — (formerly, in Britain) a scheme, run by the Training Agency, to provide vocational training for unemployed 16–17-year-olds
- zero-emission vehicle — a vehicle, as an automobile, that does not directly produce atmospheric pollutants. Abbreviation: ZEV.