18-letter words containing n, a, i
- 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.
- provincial council — (formerly) a council administering any of the New Zealand provinces
- provision merchant — a person or company in the business of retailing food and other provisions
- pseudo-anarchistic — a person who advocates or believes in anarchy or anarchism.
- pseudoappendicitis — inflammation of the vermiform appendix.
- pseudointellectual — a person exhibiting intellectual pretensions that have no basis in sound scholarship.
- ptomaine poisoning — (erroneously) food poisoning thought to be caused by ptomaine.
- public corporation — a corporation, owned and operated by a government, established for the administration of certain public programs.
- public examination — an examination, such as a GCSE exam, that is set by a central examining board
- publicity campaign — an effort to convey information to the public
- publishing company — a firm which publishes books
- pull one's head in — the upper part of the body in humans, joined to the trunk by the neck, containing the brain, eyes, ears, nose, and mouth.
- pulmonary embolism — the blockage of a pulmonary artery, often by a blood clot, that stops the flow of blood to the lungs and which can result in death if untreated
- pulmonic airstream — a current of lung air set in motion by the respiratory muscles in the production of speech.
- punishment beating — a form of corporal punishment carried out by a paramilitary organization on a member of another sectarian organization, usually in Northern Ireland
- purchasing officer — the member of staff in an organization who is responsible for buying goods or products
- puvis de chavannes — Puvis de [py-vee duh] /püˈvi də/ (Show IPA), Puvis de Chavannes, Pierre.
- 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).
- quality controller — a person responsible for checking that the goods or services produced by an organization are of an acceptable standard
- quantity surveying — the action or profession of a person who estimates the cost of the materials and labour necessary for a construction job
- quantum efficiency — the number of electrons released by a photocell per photon of incident radiation of a given energy
- quantum statistics — the branch of statistical mechanics that incorporates quantum mechanics.
- 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
- 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
- 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.
- radical expression — an expression in which radical signs appear.
- radio range beacon — a radio transmitter that utilizes two or more directional antennas and transmits signals differing with direction, permitting a flier receiving a signal to determine his or her approximate bearing from the transmitter without a radio compass.
- 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.
- 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).
- range of stability — the angle to the perpendicular through which a vessel may be heeled without losing the ability to right itself.
- rape crisis centre — a place that provides support to people who have been victims of rape or other kinds of sexual abuse
- 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.