21-letter words containing w, o, l
- warm silence software — A small company run by(?) Robin Watts, producing software for the Acorn Archimedes.
- weak head normal form — (reduction, theory) (WHNF) A lambda expression is in weak head normal form (WHNF) if it is a head normal form (HNF) or any lambda abstraction. I.e. the top level is not a redex. The term was coined by Simon Peyton Jones to make explicit the difference between head normal form (HNF) and what graph reduction systems produce in practice. A lambda abstraction with a reducible body, e.g. \ x . ((\ y . y+x) 2) is in WHNF but not HNF. To reduce this expression to HNF would require reduction of the lambda body: (\ y . y+x) 2 --> 2+x Reduction to WHNF avoids the name capture problem with its need for alpha conversion of an inner lambda abstraction and so is preferred in practical graph reduction systems. The same principle is often used in strict languages such as Scheme to provide call-by-name evaluation by wrapping an expression in a lambda abstraction with no arguments: D = delay E = \ () . E The value of the expression is obtained by applying it to the empty argument list:
- weinberg-salam theory — electroweak theory.
- well-ordering theorem — the theorem of set theory that every set can be made a well-ordered set.
- west lothian question — the apparent inconsistency that members of parliament who represent Scottish constituencies are eligible to vote at Westminster on matters that relate only to England, whereas members of parliament from English constituencies are not eligible to vote on Scottish matters
- wet collodion process — a photographic process, in common use in the mid-19th century, employing a glass photographic plate coated with iodized collodion and dipped in a silver nitrate solution immediately before use.
- what the future holds — If you wonder what the future holds, you wonder what will happen in the future.
- wholesale price index — an indicator of price changes in the wholesale market
- wildlife photographer — someone that specializes in taking photographs of wild animals, especially in their natural habitats, and plants
- 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.
- with sb's compliments — If you say that you are giving someone something with your compliments, you are saying in a polite and fairly formal way that you are giving it to them, especially as a gift or a favour.
- without qualification — If something is stated or accepted without qualification, it is stated or accepted as it is, without the need for any changes.
- worth someone's while — worth someone's time, consideration, etc.; profitable in some way
- yellow lady's-slipper — a showy orchid, Cypripedium calceolus, of eastern North America, having purple-tinged yellow flowers with an inflated lip petal.
- 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.
- yellow-flowered gourd — the hard-shelled fruit of any of various plants, especially those of Lagenaria siceraria (white-flowered gourd or bottle gourd) whose dried shell is used for bowls and other utensils, and Cucurbita pepo (yellow-flowered gourd) used ornamentally. Compare gourd family.
- yellow-rumped warbler — a common North American wood warbler, Dendroica coronata, having yellow spots on the rump, crown, and sides, including a white-throated eastern subspecies (myrtle warbler) and a yellow-throated western subspecies (Audubon's warbler)
- yellow-throated vireo — an olive-green vireo, Vireo flavifrons, of eastern North America, having a bright yellow throat and breast.