20-letter words containing a, i, r, d, u
- multistep hydroplane — a motorship having a flat bottom built as a series of planes inclined forward, the ship planing on each from stem to stern as its speed increases.
- mum-and-dad investor — a small-scale non-professional investor
- neighbourhood warden — a person employed by a local authority to patrol residential areas and deal with antisocial behaviour
- net national product — the gross national product less allowance for depreciation of capital goods. Abbreviation: NNP.
- nonaccidental injury — damage, such as a bruise, burn, or fracture, deliberately inflicted on a child or an old person
- notre dame mountains — a mountain range in E Quebec, Canada, an extension of the Green Mountains in Vermont and a portion of the Appalachian Mountains: about 500 miles (800 km) long, rising about 2000 feet (610 meters).
- ode on a grecian urn — a poem (1819) by Keats.
- officer of the guard — an officer, acting under the officer of the day, who is responsible for the instruction, discipline, and performance of duty of the guard in a post, camp, or station. Abbreviation: OG, O.G.
- pappus of alexandria — 3rd century bc, Greek mathematician, whose eight-volume Synagoge is a valuable source of information about Greek mathematics
- parallel of altitude — almucantar.
- parallel of latitude — parallel (def 9).
- pedal steel (guitar) — a steel guitar mounted on legs and equipped with pedals that serve as an additional means of changing pitch
- pentobarbital sodium — a barbiturate drug used in medicine as a sedative and hypnotic. Formula: C11H17N2O3Na
- permonosulfuric acid — persulfuric acid (def 1).
- peroxysulphuric acid — a white hygroscopic crystalline unstable oxidizing acid. Formula: H2SO5
- perpendicular gothic — the style of Gothic architecture in England during the 14th and 15th centuries, characterized by tracery having vertical lines, a four-centred arch, and fan vaulting
- physical double star — two stars that appear as one if not viewed through a telescope with adequate magnification, such as two stars that are separated by a great distance but are nearly in line with each other and an observer (optical double star) or those that are relatively close together and comprise a single physical system (physical double star)
- potassium dichromate — an orange-red crystalline soluble solid substance that is a good oxidizing agent and is used in making chrome pigments and as a bleaching agent. Formula: K2Cr2O7
- pound cost averaging — a method of accumulating capital by investing a fixed sum in a particular security at regular intervals, in order to achieve an average purchase price below the arithmetic average of the market prices on the purchase dates
- prince william sound — a sound in the Gulf of Alaska, on the S coast of Alaska: S end of Trans-Alaska oil pipeline at port of Valdez.
- production agreement — a contract concerning the production or manufacture of something
- prohibited substance — a substance, such as a drug, etc, that is banned or forbidden by law or other authority
- public administrator — an official of a city, county, or state government.
- quantum field theory — any theory in which fields are treated by the methods of quantum mechanics; each field can then be regarded as consisting of particles of a particular kind, which may be created and annihilated.
- radial triangulation — triangulation based upon lines radiating from the center of each of two overlapping photographs to certain objects appearing on each photograph.
- reductio ad absurdum — a reduction to an absurdity; the refutation of a proposition by demonstrating the inevitably absurd conclusion to which it would logically lead.
- refuse disposal unit — a unit or part of a sink that disposes of waste food, etc, by grinding
- republic of maldives — a republic occupying an archipelago of 1087 coral islands in the Indian Ocean, southwest of Sri Lanka: came under British protection in 1887; became independent in 1965 and a republic in 1968; member of the Commonwealth (1982–2016). The economy and infrastructure were severely damaged in the Indian Ocean tsunami of December 2004. Official language: Divehi. Official religion: (Sunni) Muslim. Currency: rufiyaa. Capital: Malé. Pop: 393 988 (2013 est). Area: 298 sq km (115 sq miles)
- rheumatoid arthritis — a chronic autoimmune disease characterized by inflammation of the joints, frequently accompanied by marked deformities, and ordinarily associated with manifestations of a general, or systemic, affliction.
- ring wall foundation — A ring wall foundation is a base made of concrete, used to put large tanks on.
- rough-winged swallow — either of two New World swallows of the genus Stelgidopteryx, having outer primary feathers with small barblike hooks on the margins.
- schrodinger equation — the wave equation of nonrelativistic quantum mechanics. Also called Schrödinger wave equation. Compare wave equation (def 2).
- schwarzschild radius — the radius at which a gravitationally collapsing celestial body becomes a black hole.
- secure accommodation — an institution where young offenders are kept in custody
- serious fraud office — a UK government office responsible for investigating and prosecuting serious fraud cases
- serra da mantiqueira — a mountain range in SE Brazil, running parallel to the coast. Highest point, 9140 feet (2785 meters).
- shareholders' equity — Shareholders' equity is the total amount of ownership investment in a company.
- shoulder-length hair — hair that reaches a person's shoulders
- sierra madre del sur — a plateau mountain range in Guerrero and Oaxaca states, S Mexico. Highest peak 12,149 feet (3703 meters).
- social security card — a card that contains details of a person's social security number
- sodium fluoroacetate — a white, amorphous, water-soluble, poisonous powder, C 2 H 2 FO 2 Na, used as a rodenticide.
- sodium meta-arsenite — sodium arsenite.
- south orkney islands — an uninhabited group of islands in the S Atlantic, southeast of Cape Horn: formerly a dependency of the Falkland Islands; part of the British Antarctic Territory since 1962 (claims are suspended under the Antarctic Treaty). Area: 621 sq km (240 sq miles)
- suitland-silver hill — a city in central Maryland, near Washington, D.C.
- summary jurisdiction — the right a court has to adjudicate immediately upon some matter arising during its proceedings
- tax-deferred annuity — an annuity that enables one to purchase an insurance product that will earn interest, with the tax obligation deferred until withdrawals begin, usually at retirement. Abbreviation: TDA.
- temperature gradient — rate of change of temperature with distance.
- terrestrial guidance — a method of missile or rocket guidance in which the flight path is controlled by reference to the strength and direction of the earth's gravitational or magnetic field
- the founding fathers — any of the men who were members of the U.S. Constituional Convention of 1787
- the garment industry — the manufacturing of items of clothing