21-letter words containing a, d, f, r
- peroxydisulfuric acid — persulfuric acid (def 2).
- piero della francesca — Piero della [pee-air-oh del-uh;; Italian pye-raw del-lah] /piˈɛər oʊ ˈdɛl ə;; Italian ˈpyɛ rɔ ˈdɛl lɑ/ (Show IPA), (Piero dei Franceschi) c1420–92, Italian painter.
- place of safety order — (in Britain) under the Children and Young Persons Act 1969, an order granted by a justice to a person or agency granting authority to detain a child or young person and take him or her to a place of safety for not more than 28 days, because of the child's actual or likely ill-treatment or neglect, etc
- radius of convergence — a positive number so related to a given power series that the power series converges for every number whose absolute value is less than this particular number.
- record of achievement — a statement of the personal and educational development of each pupil
- road traffic accident — an accident involving vehicles
- rutherford scattering — the scattering of an alpha particle through a large angle with respect to the original direction of motion of the particle, caused by an atom (Rutherford atom) with most of the mass and all of the positive electric charge concentrated at a center or nucleus.
- saint-maur-des-fosses — a town in N central France, near Paris, on the Marne River.
- school of hard knocks — the experience gained from living, especially from disappointment and hard work, regarded as a means of education: The only school he ever attended was the school of hard knocks.
- semantic differential — a technique for measuring the connotative meaning of concepts by having an individual rate each concept on a series of graduated scales, each scale defined by a pair of polar adjectives, as good–bad or strong–weak.
- silicon tetrafluoride — a colorless, fuming gas, SiF 4 , used chiefly in the manufacture of fluosilicic acid.
- sing a different tune — a succession of musical sounds forming an air or melody, with or without the harmony accompanying it.
- sovereign wealth fund — an investment fund created using the financial assets of a national government
- staffordshire terrier — former name of American Staffordshire terrier.
- stem-and-leaf diagram — a histogram in which the data points falling within each class interval are listed in order
- step-down transformer — a device that transfers an alternating current from one circuit to one or more other circuits with a decrease of voltage
- surface friction drag — the part of the drag on a body moving through a fluid that is dependent on the nature of the surface of the body
- surface-to-underwater — (of a missile, message, etc.) traveling from the surface of the earth to a target underwater.
- the break of day/dawn — The break of day or the break of dawn is the time when it begins to grow light after the night.
- the fall of the cards — the chance distribution of cards in a given deal
- the order of the bath — an order of knighthood founded by George I in 1725. It consists of the sovereign, the Great Master, and three classes of member: Knight (or Dame) Grand Cross, Knight (or Dame) Commander, and Companion
- the san andreas fault — a geological fault in California
- theater of the absurd — theater in which standard or naturalistic conventions of plot, characterization, and thematic structure are ignored or distorted in order to convey the irrational or fictive nature of reality and the essential isolation of humanity in a meaningless world.
- theatre of the absurd — drama in which normal conventions and dramatic structure are ignored or modified in order to present life as irrational or meaningless
- tide-generating force — the difference between the force of gravity exerted by the moon or the sun on a particle of water in the ocean and that exerted on an equal mass of matter at the centre of the earth. The lunar tide-generating forces are about 2.2 times greater than are the solar ones
- to lay down your life — If someone lays down their life for another person, they die so that the other person can live.
- to risk life and limb — If someone risks life and limb, they do something very dangerous that may cause them to die or be seriously injured.
- to take your mind off — If something takes your mind off a problem or unpleasant situation, it helps you to forget about it for a while.
- tripartite and fretty — (of a cross) having the limbs divided into three longitudinal strips each, intermingled in the manner of those in a cross parted and fretty.
- universal disk format — (storage, standard) (UDF) A CD-ROM file system standard that is required for DVD ROMs. UDF is the OSTA's replacement for the ISO 9660 file system used on CD-ROMs, but will be mostly used on DVD. DVD multimedia disks use UDF to contain MPEG audio and video streams. To read DVDs you need a DVD drive, the kernel driver for the drive, MPEG video support, and a UDF driver. DVDs containing both UDF filesystems and ISO 9660 filesystems can be read without UDF support. UDF can also be used by CD-R and CD-RW recorders in packet writing mode.
- university of iceland — (body, education) The Home of Fjolnir.
- 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:
- what the future holds — If you wonder what the future holds, you wonder what will happen in the future.
- whip-and-tongue graft — a graft prepared by cutting both the scion and the stock in a sloping direction and inserting a tongue in the scion into a slit in the stock.
- wildlife photographer — someone that specializes in taking photographs of wild animals, especially in their natural habitats, and plants