19-letter words containing a, t, o, r, n
- proton-proton chain — a series of thermonuclear reactions, responsible for the energy production in stars like the sun, in which the nuclei of hydrogen atoms are transformed into helium nuclei by sequential addition of single hydrogen nuclei.
- pseudo-conservative — disposed to preserve existing conditions, institutions, etc., or to restore traditional ones, and to limit change.
- pseudo-experimental — pertaining to, derived from, or founded on experiment: an experimental science.
- pseudo-intransitive — denoting an occurrence of a normally transitive verb in which a direct object is not explicitly stated or forms the subject of the sentence, as in Margaret is cooking or these apples cook well
- put a figure on sth — When you put a figure on an amount, you say exactly how much it is.
- pyrenees-orientales — a department in S France. 1600 sq. mi. (4145 sq. km). Capital: Perpignan.
- pythagorean theorem — Pythagoras's Theorem
- quantum electronics — the application of quantum mechanics and quantum optics to the study and design of electronic devices
- queen's regulations — (in Britain and certain other Commonwealth countries when the sovereign is female) the code of conduct for members of the armed forces
- radiation potential — the potential in volts that must be applied to an atom or molecule to cause it to emit radiation at one of its characteristic frequencies.
- radiational cooling — the cooling of the earth's surface and adjacent air, primarily at night, caused by a loss of heat due to surface emission of infrared radiation.
- rag-tag and bobtail — the riffraff; rabble: The ragtag and bobtail of every nation poured into the frontier in search of gold.
- rap on the knuckles — a mild reprimand or light sentence
- rate of penetration — The rate of penetration is the speed with which a drill bit can break the rock under it.
- reactive depression — depression occurring in response to some situational stress, as loss of one's job.
- reconceptualization — to form into a concept; make a concept of.
- recording secretary — an officer charged with keeping the minutes of meetings and responsible for the records.
- recurrence relation — (mathematics) An equation that defines each element of a sequence in terms of one or more earlier elements. E.g. The Fibonacci sequence, X[1] = 1 X[2] = 1 X[n] = X[n-1] + X[n-2] Some recurrence relations can be converted to "closed form" where X[n] is defined purely in terms of n, without reference to earlier elements.
- reduction potential — (in a galvanic cell) the potential of the electrode at which reduction occurs.
- register allocation — (compiler, algorithm) The phase of a compiler that determines which values will be placed in registers. Register allocation may be combined with register assignment. This problem can be shown to be isomorphic to graph colouring by relating values to nodes in the graph and registers to colours. Values (nodes) which must be valid simultaneously are linked by edges and cannot be stored in the same register (coloured the same). See also register dancing and register spilling.
- registration number — number on vehicle licence plate
- reindustrialization — the revitalization of an industry or industrial society through government aid and tax incentives, modernization of factories and machinery, etc.
- relational calculus — (database) An operational methodolgy, founded on predicate calculus, dealing with descripitive expressions that are equivalent to the operations of relational algebra. Codd's reduction algorithm can convert from relational calculus to relational algebra. Two forms of the relational calculus exist: the tuple calculus and the domain calculus.
- relational database — an electronic database comprising multiple files of related information, usually stored in tables of rows (records) and columns (fields), and allowing a link to be established between separate files that have a matching field, as a column of invoice numbers, so that the two files can be queried simultaneously by the user.
- relational language — (language) Any kind of programming language that specifies output in terms of some property and some arguments. For example, if Tom has two brothers, Dick and Harry, a relational language will respond to the query "Who is Tom's brother?" with either Dick or Harry. Notice that unlike functional languages, relational languages do not require a unique output for each predicate/argument pair. Prolog is the best known relational language.
- relative complement — the set of elements contained in a given set that are not elements of another specified set.
- relief organization — humanitarian group
- religious education — religion as school subject
- relocation expenses — Relocation expenses are a sum of money that a company pays to someone who moves to a new area in order to work for the company. The money is to help them pay for moving house.
- repeat prescription — A repeat prescription is a prescription for a medicine that you have taken before or that you use regularly.
- representationalism — Also called representative realism. Epistemology. the view that the objects of perception are ideas or sense data that represent external objects, especially the Lockean doctrine that the perceived idea represents exactly the primary qualities of the external object.
- republic of vietnam — the name (from 1955–75) for South Vietnam, as an independent republic, following the division of the country in 1954 into North Vietnam and South Vietnam
- reserved occupation — in time of war, an occupation from which one will not be called up for military service
- resistance movement — a movement fighting (for freedom, etc), often secretly or illegally, against an invader in an occupied country or against the country's government, etc
- resonance radiation — radiation emitted by an atom or molecule, having the same frequency as that of an incident particle, as a photon, and usually involving a transition to the lowest energy level of the atom or molecule.
- resonant-jet engine — resojet engine.
- resorcinolphthalein — fluorescein.
- respiratory pigment — any of several colored protein substances, as hemoglobin and hemocyanin, in the circulatory system of animals and some plants, that combine reversibly with oxygen that is carried to the tissues
- reticular formation — a network of neurons in the brainstem involved in consciousness, regulation of breathing, the transmission of sensory stimuli to higher brain centers, and the constantly shifting muscular activity that supports the body against gravity.
- reticuloendothelial — pertaining to, resembling, or involving cells of the reticuloendothelial system.
- reversible reaction — a reaction that, depending on ambient conditions, can proceed in either of two directions: the production of the reaction products from the reactants, or the production of the original reactants from the formed reaction products. Compare equilibrium (def 4).
- rhetorical question — a question asked solely to produce an effect or to make an assertion and not to elicit a reply, as “What is so rare as a day in June?”.
- riemannian geometry — Also called elliptic geometry. the branch of non-Euclidean geometry that replaces the parallel postulate of Euclidean geometry with the postulate that in a plane every pair of distinct lines intersects. Compare hyperbolic geometry.
- right circular cone — a cone whose surface is generated by lines joining a fixed point to the points of a circle, the fixed point lying on a perpendicular through the center of the circle.
- rio grande do norte — a state in E Brazil. 20,464 sq. mi. (53,000 sq. km). Capital: Natal.
- rocky mountain goat — a long-haired, white, antelopelike wild goat, Oreamnos americanus, of mountainous regions of western North America, having short, black horns.
- romanian tenderloin — a cut of beef consisting of the diaphragm muscle.
- royal correspondent — a journalist who reports on matters relating to royalty
- sacramento sturgeon — white sturgeon.
- samoa standard time — a standard time used in the zone which includes American Samoa, corresponding to the mean solar time of the 165th meridian west of Greenwich, England: it is eleven hours behind Greenwich time