21-letter words containing a, d, i, s, o
- reading comprehension — a text that students use to help them improve their reading skills, by reading it and answering questions relating to the text. Sometimes used as a test or examination of reading skills. A reading comprehension can be in the student's own or another language
- registration document — a document giving identification details of a motor vehicle, including its manufacturer, date of registration, engine and chassis numbers, and owner's name
- residual unemployment — the unemployment that remains in periods of full employment, as a result of those mentally, physically, or emotionally unfit to work
- revillagigedo islands — an uninhabited island group belonging to Mexico, in the Pacific Ocean, SSW of the Baja California peninsula: Socorro is the largest island. 320 sq. mi. (830 sq. km).
- ring-around-the-rosey — a children's game in which the players sing while going around in a circle and squat when the lyrics “all fall down” are sung.
- roodepoort-maraisburg — a city in S Transvaal, in the NE Republic of South Africa.
- 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.
- s-k reduction machine — An abstract machine defined by Professor David Turner to evaluate combinator expressions represented as binary graphs. Named after the two basic combinators, S and K.
- safe in the knowledge — If you do something safe in the knowledge that something else is the case, you do the first thing confidently because you are sure of the second thing.
- saint-maur-des-fosses — a town in N central France, near Paris, on the Marne River.
- sampling distribution — the distribution of a statistic based on all possible random samples that can be drawn from a given population.
- sanitation department — the department of local government responsible for collecting and disposing of refuse
- sao jose do rio preto — a city in SE Brazil, NW of São Paulo.
- sao tome and principe — Democratic Republic of, a republic in W Africa, comprising the islands of São Tomé and Príncipe, in the Gulf of Guinea, N of the equator: a former overseas province of Portugal; gained independence in 1975. 372 sq. mi. (964 sq. km). Capital: São Tomé.
- scalar triple product — the volume of the parallelepiped defined by three given vectors, u, v, and w, usually represented as u·v 1 (v×w), [ uvw ], or (uvw), where × denotes a cross product and · denotes an inner product.
- schema definition set — (SDS) Something in Portable Common Tool Environment.
- scorched earth policy — a military practice of devastating the property and agriculture of an area before abandoning it to an advancing enemy.
- scorched-earth policy — a military practice of devastating the property and agriculture of an area before abandoning it to an advancing enemy.
- seating accommodation — the provision of seats for people in a room, building, etc
- secondary containment — Secondary containment is a system for dealing with hazardous spills.
- serbia and montenegro — a former country in SE Europe, consisting of the republics of Serbia and Montenegro; replaced the Federal Republic of Yugoslavia in 2003, and dissolved in 2006 following Montenegro’s decision to secede
- shams ud-din mohammed — (Shams ud-din Mohammed) c1320–89? Persian poet.
- sheppard's correction — a method of correcting the bias in standard deviations and higher moments of distributions that arises from grouping values of the variable.
- sierra madre oriental — the system of mountains in the east of Mexico
- silicon tetrachloride — a colorless, fuming liquid, SiCl 4 , used chiefly for making smoke screens and various derivatives of silicon.
- silicon tetrafluoride — a colorless, fuming gas, SiF 4 , used chiefly in the manufacture of fluosilicic acid.
- sinusoidal projection — an equal-area projection in which parallels are straight lines spaced at regular intervals, the central meridian is a straight line one-half the length of the equator, and the other meridians are curves symmetrical to the central meridian.
- snappy video snapshot — (hardware) (registered trademark) A frame grabber for the IBM PC designed and marketed by Play, Inc..
- snr bandwidth product — (communications) The integral of the SNR over frequency. The SNR bandwidth product is an important limit in the capacity of a communication channel.
- social administration — the administration and maintenance of issues to do with social policies and welfare
- sodium metabisulphite — an inorganic compound with the chemical formula Na2S2O5 that is used as a preservative, antioxidant and disinfectant
- somatization disorder — a mental illness, usually beginning before age 20, characterized by multiple physical complaints for which no physical causes can be found and often leading to unnecessary treatment or surgery and to severe disability.
- someone's name is mud — someone is disgraced
- sovereign wealth fund — an investment fund created using the financial assets of a national government
- special correspondent — a journalist who covers stories firsthand from a war zone
- spherical coordinates — Usually, spherical coordinates. any of three coordinates used to locate a point in space by the length of its radius vector and the angles this vector makes with two perpendicular polar planes.
- spotted alfalfa aphid — a pale yellowish aphid, Therioaphis maculata, of the southern U.S., especially west of the Mississippi River, that is marked with black spots and has fine spines on its back: a pest mainly of alfalfa and some other legumes, as clover.
- staffordshire terrier — former name of American Staffordshire terrier.
- statutory declaration — a declaration made under statutory authority before a justice of the peace or commissioner for oaths which may in certain cases be substituted for a statement on oath
- stock list department — (in an American stock exchange) the department dealing with monitoring compliance with its listing requirements and rules
- strategic air command — a U.S. Air Force command charged with intercontinental air strikes, especially nuclear attacks.
- student participation — the extent to which students participate or involve themselves in a class, course, etc
- suction and curettage — a technique involving extraction of the fetus through a suction tube, used to perform abortions during the early stages of pregnancy.
- 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
- synchrotron radiation — electromagnetic radiation emitted by charged particles as they pass through magnetic fields.
- take sb at their word — If you take someone at their word, you believe what they say, when they did not really mean it or when they meant something slightly different.
- terrestrial radiation — long-wave electromagnetic radiation in the form of heat emitted from the earth's surface and atmosphere.
- the antipodes islands — a group of small uninhabited islands in the South Pacific, southeast of and belonging to New Zealand. Area: 62 sq km (24 sq miles)
- thermal decomposition — Thermal decomposition is the process in which a chemical species breaks down when its temperature is increased.
- threshold wage policy — a policy whereby wages are increased in accordance with inflation