18-letter words containing a, d, r, t
- potassium fluoride — a white, crystalline, hygroscopic, toxic powder, KF, used chiefly as an insecticide, a disinfectant, and in etching glass.
- potential gradient — the rate of change of potential with respect to distance in the direction of greatest change.
- pour cold water on — If someone pours cold water on a plan or idea, they criticize it so much that people lose their enthusiasm for it.
- predation pressure — the effect of predation upon a population, resulting in the decrease in size of that population.
- predicate calculus — predicate logic
- prepare the ground — make conditions ready
- presenile dementia — a form of dementia, of unknown cause, starting before a person is old
- preservation order — In Britain, a preservation order is an official order that makes it illegal for anyone to alter or destroy something such as an old building or an area of countryside.
- presidential suite — a suite of rooms, as in a hotel, suitable for a president or other head of state.
- prestidigitization — /pres`t*-di"j*-ti:-zay"sh*n/ 1. A term coined by Daniel Klein <[email protected]> for the act of putting something into digital notation via sleight of hand. 2. Data entry through legerdemain.
- primate of england — a title of the archbishop of Canterbury.
- product acceptance — the verification or acceptance that a manufactured item meets required specifications or standards and is usable for its purpose
- production company — an organization which produces, films, plays, television or radio programmes
- production manager — a supervisor of the budget, crew and other details in the production of a film or play
- programme of study — the prescribed syllabus that pupils must be taught at each key stage in the National Curriculum
- protocol data unit — (PDU) A packet of data passed across a network. The term implies a specific layer of the OSI seven layer model and a specific protocol.
- provably difficult — The set or property of problems for which it can be proven that no polynomial-time algorithm exists, only exponential-time algorithms.
- pseudo-anarchistic — a person who advocates or believes in anarchy or anarchism.
- put heads together — the upper part of the body in humans, joined to the trunk by the neck, containing the brain, eyes, ears, nose, and mouth.
- pyramus and thisbe — (in Greek legend) two lovers of Babylon: Pyramus, wrongly supposing Thisbe to be dead, killed himself and she, encountering him in his death throes, did the same
- 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).
- quarry-tiled floor — a floor covered with square or diamond-shaped unglazed floor tiles
- 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
- quinacrine mustard — a nitrogen mustard derived from mepacrine and used as a stain for chromosomes
- racially motivated — motivated by (the hate or prejudice of) someone's race
- radiant efficiency — the ratio of the power emitted by a source of radiation to the power consumed by it
- 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.
- radioactive series — a succession of elements initiated in the radioactive decay of a parent, as thorium or uranium, each of which decays into the next until a stable element, usually lead, is produced.
- 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.
- ragtag and bobtail — the riffraff; rabble: The ragtag and bobtail of every nation poured into the frontier in search of gold.
- rail rapid transit — a system of rail transit within an urban area that has exclusive right of way either below, above, or on the ground and so is capable of relatively high operating speed. Abbreviation: RRT.
- 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).
- random walk theory — the theory that the future movement of share prices does not reflect past movements and therefore will not follow a discernible pattern
- rapid eye movement — rapidly shifting, continuous movements of the eyes beneath closed lids during the stage of sleep characterized by dreaming.
- rear its ugly head — the upper part of the body in humans, joined to the trunk by the neck, containing the brain, eyes, ears, nose, and mouth.
- redevelopment area — an urban area in which all or most of the buildings are demolished and rebuilt
- 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
- redundancy payment — a sum of money given by an employer to an employee who has been made redundant: usually calculated on the basis of the employee's rate of pay and length of service
- refrigerated lorry — a lorry which is chilled in the back as for storing food
- registered charity — official aid organization
- registered company — a company which has officially registered its business
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- repayment schedule — a document detailing the specific terms of a borrower's loan, such as monthly payment, interest rate, due dates etc