21-letter words containing a, d, i
- public address system — loudspeaker
- public administration — the implementation of public policy, largely by the executive branch.
- public-address system — a combination of electronic devices that makes sound audible via loudspeakers to many people, as in an auditorium or out of doors.
- pulse code modulation — a form of modulation that transforms a wave-form, as an audio signal, into a binary signal in which information is conveyed by a coded order of pulses for transmission, storage on a disk, or processing by a computer. Abbreviation: PCM.
- pulse-code modulation — a form of modulation that transforms a wave-form, as an audio signal, into a binary signal in which information is conveyed by a coded order of pulses for transmission, storage on a disk, or processing by a computer. Abbreviation: PCM.
- pulse-time modulation — radio transmission in which the carrier is modulated to produce a series of pulses timed to transmit the amplitude and pitch of a signal. Abbr.: PTM.
- purchasing department — the group of staff within an organization that is responsible for buying goods or products
- push up (the) daisies — to be dead and buried
- put in the hard yards — to make a great effort to achieve an end
- pyrenean mountain dog — a large heavily built dog of an ancient breed originally used to protect sheep from wild animals: it has a long thick white coat with a dense ruff
- quadralay corporation — (company) The developers of GWHIS. Telephone: +1 512-346-9199. Fax: +1 512-346-8990.
- racial discrimination — prejudice based on race
- 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.
- ralph roister doister — a play (1553?) by Nicholas Udall: the earliest known English comedy.
- rayleigh distribution — (mathematics) A curve that yields a good approximation to the actual labour curves on software projects.
- 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
- record of achievement — a statement of the personal and educational development of each pupil
- reduced circumstances — If you say that someone is living in reduced circumstances, you mean that they do not have as much money as they used to have.
- redwood national park — a national park in N California: redwood forest with some of the world's tallest trees. 172 sq. mi. (445 sq. km).
- 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
- relational data model — (database) (Or "relational model") A data model introduced by E.F. Codd in 1970, particularly well suited for business data management. In this model, data are organised in tables. The set of names of the columns is called the "schema" of the table. Here is an example table with the schema (account number, amount) and 3 lines. account number amount -------------- --------- 12343243546456 +30000.00 23149875245824 +2345.33 18479827492874 -123.25 The data can be manipulated using a relational algebra. SQL is a standard language for talking to a database built on the relational model (a "relational database").
- residual unemployment — the unemployment that remains in periods of full employment, as a result of those mentally, physically, or emotionally unfit to work
- retarded acceleration — velocity increase constrained by opposing forces such as wind resistance or braking
- 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).
- richard coeur de lion — ("Richard the Lion-Hearted"; "Richard Coeur de Lion") 1157–99, king of England 1189–99.
- right-angled triangle — a triangle one angle of which is a right angle
- ring down the curtain — to lower the curtain at the end of a theatrical performance
- 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.
- rio de la plata river — Rí·o de la [ree-aw th e lah] /ˈri ɔ ðɛ lɑ/ (Show IPA) an estuary on the SE coast of South America between Argentina and Uruguay, formed by the Uruguay and Paraná rivers, about 185 miles (290 km) long.
- road traffic accident — an accident involving vehicles
- roodepoort-maraisburg — a city in S Transvaal, in the NE Republic of South Africa.
- royal victorian order — (in Britain) an order of chivalry founded by Queen Victoria in 1896, membership of which is conferred for special services to the sovereign
- 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.
- sail against the wind — to sail a course that slants slightly away from the true direction of the wind; sail closehauled
- saint valentine's day — February 14, observed in honor of St. Valentine as a day for the exchange of valentines and other tokens of affection.
- 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
- santa barbara islands — group of nine islands, & many islets, off the SW coast of Calif.
- 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.
- satellite dish aerial — a parabolic aerial for reception from or transmission to an artificial satellite
- 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.
- sealed-beam headlight — a headlight in which the reflector and lens are hermetically sealed together with the filament in a single unit.
- seating accommodation — the provision of seats for people in a room, building, etc