18-letter words containing i, o, n, t, r
- qattara depression — a desert basin in the Libyan Desert, in NW Egypt: lowest point is 435 feet (133 meters) below sea level. 6950 sq. mi. (18,000 sq. km).
- quadratic equation — an equation containing a single variable of degree 2. Its general form is ax 2 + bx + c = 0, where x is the variable and a, b, and c are constants (a ≠ 0).
- quality controller — a person responsible for checking that the goods or services produced by an organization are of an acceptable standard
- quartz-iodine lamp — a type of tungsten-halogen lamp containing small amounts of iodine and having a quartz envelope, operating at high temperature and producing an intense light for use in car headlamps, etc
- quite the contrary — not at all, the very opposite
- rabbit's-foot fern — hare's-foot fern.
- rabbit-proof fence — a fence through which rabbits are unable to pass
- racial segregation — social policy: separation of races
- radiation exposure — exposure to radiant energy or to the particles emitted in the transfer of radiant energy, esp the particles and gamma rays emitted in nuclear decay; exposure to radioactive substances
- radiation pressure — the pressure exerted on a surface by electromagnetic radiation or by sound waves.
- radiation sickness — sickness caused by irradiation with x-rays or other nuclear radiation as a result of therapeutic treatment, accidental exposure, or a nuclear bomb explosion and characterized by nausea, vomiting, headache, cramps, diarrhea, loss of hair and teeth, destruction of white blood cells, and prolonged hemorrhage.
- radioactive dating — any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.
- radiocarbon dating — the determination of the age of objects of organic origin by measurement of the radioactivity of their carbon content.
- radiocommunication — communication by means of radio waves
- radiometric dating — any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.
- radius of gyration — the distance from an axis at which the mass of a body may be assumed to be concentrated and at which the moment of inertia will be equal to the moment of inertia of the actual mass about the axis, equal to the square root of the quotient of the moment of inertia and the mass.
- raffinate recovery — Raffinate recovery is the use of a substance which is left after a process is complete and the desired substances have been removed.
- ragtag and bobtail — the riffraff; rabble: The ragtag and bobtail of every nation poured into the frontier in search of gold.
- rain cats and dogs — water that is condensed from the aqueous vapor in the atmosphere and falls to earth in drops more than 1/50 inch (0.5 mm) in diameter. Compare drizzle (def 6).
- range of stability — the angle to the perpendicular through which a vessel may be heeled without losing the ability to right itself.
- rapid eye movement — rapidly shifting, continuous movements of the eyes beneath closed lids during the stage of sleep characterized by dreaming.
- rational operation — any of the mathematical operations of addition, subtraction, multiplication, and division.
- reaction formation — a behavioral tendency developed in direct opposition to a repressed impulse.
- reactive component — the component in an alternating-current circuit that does not contribute power because it is 90° out of phase with the voltage or current.
- recess appointment — a person appointed to an office by the President of the United States without approval from the Senate because the Senate is in recess
- recharacterization — portrayal; description: the actor's characterization of a politician.
- reciprocating pump — A reciprocating pump is a pump which uses a backward and forward movement to move a fluid.
- recovery operation — the process of locating and retrieving bodies, esp following an explosion or natural disaster
- recruiting officer — a person whose job is to recruit staff, esp on behalf of the military
- recursive function — a function defined in terms of the repeated application of a number of simpler functions to their own values, by specifying a base clause and a recursion formula
- reduction division — the first division of meiosis in which the number of chromosomes is reduced to half the original number.
- reduction strategy — (theory) An algorithm for deciding which redex(es) to reduce next. Different strategies have different termination properties in the presence of recursive functions or values. See string reduction, normal order reduction, applicative order reduction, parallel reduction
- reentering polygon — a polygon having one or more reentering angles.
- reference counting — (programming) A garbage collection technique where each memory cell contains a count of the number of other cells which point to it. If this count reaches zero the cell is freed and its pointers to other cells are followed to decrement their counts, and so on recursively. This technique cannot cope with circular data structures. Cells in such structures refer (indirectly) to themselves and so will never have a zero reference count. This means they would never be reclaimed, even when there are no references from outside the structure.
- reflection density — a measure of the extent to which a surface reflects light or other electromagnetic radiation, equal to the logarithm to base ten of the reciprocal of the reflectance
- regional enteritis — Crohn's disease.
- registered company — a company which has officially registered its business
- registration plate — a plate mounted on the front and back of a motor vehicle bearing the registration number
- regression testing — (programming) Part of the test phase of software development where, as new modules are integrated into the system and the added functionality is tested, previously tested functionality is re-tested to assure that no new module has corrupted the system.
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- relational algebra — (database, theory) A family of algebra with a well-founded semantics used for modelling the data stored in relational databases, and defining queries on it. The main operations of the relational algebra are the set operations (such as union, intersection, and cartesian product), selection (keeping only some lines of a table) and the projection (keeping only some columns). The relational data model describes how the data is structured.
- relative minor key — a minor key that has the same key signature as a major key, but a different tonic
- remains to be seen — If you say that it remains to be seen whether something will happen, you mean that nobody knows whether it will happen.
- report an accident — If you report an accident, you inform an insurer or the police or other authorities that an accident has occurred.
- reprocessing plant — a plant where materials are treated in order to make them reusable
- reproduction proof — repro proof.
- rescind a contract — If an insurer rescinds an insurance contract, it terminates it because facts have been concealed or misrepresented by the proposer.
- residential school — (in Canada) a boarding school maintained by the Canadian government for Indian and Inuit children from sparsely populated settlements
- restoration comedy — English comedy of the period of the Restoration, stressing manners and social satire.
- restraint of trade — action tending to interrupt the free flow of goods and services, as by price fixing and other practices that have the effect of reducing competition.