21-letter words containing o, r, a, i
- quantum teleportation — a hypothetical technique to instantly transfer properties from one quantum system to another without contact, or to transfer a quantum state to an arbitrarily distant location.
- 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.
- range of significance — the set of subjects for which a given predicate is intelligible
- 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
- real operating system — (operating system, abuse) The sort the speaker is used to. People from the BSDophilic academic community are likely to issue comments like "System V? Why don't you use a *real* operating system?", people from the commercial/industrial Unix sector are known to complain "BSD? Why don't you use a *real* operating system?", and people from IBM object "Unix? Why don't you use a *real* operating system?" See holy wars, religious issues, proprietary, Get a real computer!.
- reciprocal inhibition — the theory that the pairing of an anxiety-provoking stimulus with anxiety-reducing reactions will weaken the association between the stimulus and the anxiety.
- recompression chamber — hyperbaric chamber.
- reconnaissance flight — a flight made by an aircraft in order to obtain military information about a particular place
- reconnaissance patrol — a patrol made by soldiers in order to obtain military information about a particular place
- record of achievement — a statement of the personal and educational development of each pupil
- 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
- rehabilitation centre — a centre or clinic where people with an alcohol or drug addiction are treated
- reinforcement therapy — a behavior modification technique in which appropriate behavior is strengthened through systematic reinforcement.
- 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").
- relaxation oscillator — a nonsinusoidal oscillator, the timing of which is controlled by the charge and discharge time constants of resistance and capacitance components
- repatriation expenses — Repatriation expenses are the costs involved in transporting a claimant or their body back to their own country after they have been injured or killed in a foreign country.
- replacement algorithm — The method used to determine which entry in an associative cache to flush to main memory when it is desired to cache a new block of data. The "least recently used" algorithm flushed the block which has not been accessed for the longest time. A random replacement algorithm picks any block with equal probability.
- 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
- reverberation chamber — a room with walls that reflect sound. It is used to make acoustic measurements and as a source of reverberant sound to be mixed with direct sound for recording or broadcasting
- reverse polish syntax — postfix notation
- 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.
- 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
- rocky mountain locust — a migratory locust, Melanoplus spretus, that occurs in North America, especially the Great Plains, where swarms cause great damage to crops and other vegetation.
- rocky mountain oyster — mountain oyster.
- rolling in the aisles — (of an audience) overcome with laughter
- roman catholic church — the Christian church of which the pope, or bishop of Rome, is the supreme head.
- 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.
- saint anthony's cross — tau cross.
- saint-maur-des-fosses — a town in N central France, near Paris, on the Marne River.
- salam-weinberg theory — the electroweak theory.
- sampling distribution — the distribution of a statistic based on all possible random samples that can be drawn from a given population.
- san gabriel mountains — a mountain range in S California, N of Los Angeles. Highest peak, San Antonio Peak, 10,080 feet (3072 meters).
- san gorgonio mountain — a mountain in S California: highest peak in the San Bernardino Mountains. 11,502 feet (3506 meters).
- 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.
- saponification number — the number of milligrams of potassium hydroxide required to saponify one gram of a given ester, especially a glyceride.
- satisficing behaviour — the form of behaviour demonstrated by firms who seek satisfactory profits and satisfactory growth rather than maximum profits