21-letter words containing w, a, l
- warm silence software — A small company run by(?) Robin Watts, producing software for the Acorn Archimedes.
- watenstedt-salzgitter — former name of Salzgitter.
- water-vascular system — a system of closed, fluid-filled tubes and ducts of echinoderms used in clinging, locomotion, feeding, and respiration.
- 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.
- 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
- west university place — a city in SE Texas.
- what the future holds — If you wonder what the future holds, you wonder what will happen in the future.
- whistling in the dark — If you say that someone is whistling in the dark, you mean that they are trying to remain brave and convince themselves that the situation is not as bad as it seems.
- white-knuckle paddler — an inexpert and timid canoeist.
- 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).
- with a capital letter — (used to give emphasis to a statement)
- without qualification — If something is stated or accepted without qualification, it is stated or accepted as it is, without the need for any changes.
- yellow lady's-slipper — a showy orchid, Cypripedium calceolus, of eastern North America, having purple-tinged yellow flowers with an inflated lip petal.
- 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.