17-letter words containing a, r, c, f, o
- protection factor — a figure representing the relative degree of protection from the sun's rays afforded by a particular sunscreen
- protective tariff — a tariff levied on imports to protect the domestic economy rather than to raise revenue
- purple of cassius — a purple pigment precipitated as a sol by the interaction of gold chloride and a solution of stannic acid and stannous chloride: used chiefly in the manufacture of ruby glass, ceramic glazes, and enamels.
- pyrosulfuric acid — a strong, crystalline acid, H2S2O7, prepared commercially as a heavy, oily, fuming liquid: used in making explosives and dyes, as a sulfating agent, etc.
- quadratic formula — the formula for determining theroots of a quadratic equation from its coefficients: .
- rational function — a function that can be written as the quotient of two polynomials with integral coefficients.
- receding forehead — a forehead which slopes backwards
- recursion formula — a formula for determining the next term of a sequence from one or more of the preceding terms.
- reduction formula — a formula, such as sin (90° ± A) = cos A, expressing the values of a trigonometric function of any angle greater than 90° in terms of a function of an acute angle
- reflection nebula — a cloud of interstellar gas and dust that reflects the light of neighboring stars.
- refractory period — a short period after a nerve or muscle cell fires during which the cell cannot respond to additional stimulation.
- republic of china — People's Republic of, a country in E Asia. 3,691,502 sq. mi. (9,560,990 sq. km). Capital: Beijing.
- republic of korea — a former country in E Asia, on a peninsula SE of Manchuria and between the Sea of Japan and the Yellow Sea: a kingdom prior to 1910; under Japanese rule 1910–45; now divided at 38° N into North Korea and South Korea. Compare Korean War.
- republic of palau — a republic comprising a group of islands in the W Pacific, in the W Caroline Islands; administratively part of the UN Trust Territory of the Pacific Islands 1947–87; entered into an agreement of free association with the US (1980); became fully independent in 1994. Chief island: Babelthuap. Capital: Ngerulmud on Babelthuap (functions moved from Koror in 2006). Pop: 21 108 (2013 est). Area: 476 sq km (184 sq miles)
- republic-of-china — People's Republic of, a country in E Asia. 3,691,502 sq. mi. (9,560,990 sq. km). Capital: Beijing.
- return of capital — A return of capital is a situation in which you receive back money that was previously invested.
- rheumatoid factor — an antibody that is found in the blood of many persons afflicted with rheumatoid arthritis and that reacts against globulins in the blood.
- road-fund licence — a licence showing that the tax payable in respect of a motor vehicle has been paid
- rock of gibraltar — a British crown colony comprising a fortress and seaport located on a narrow promontory near the S tip of Spain. 1.875 sq. mi. (5 sq. km).
- rotation of crops — a system of rotating in a fixed order the kinds of crops, as grain or grass, grown in the same field, to maintain soil fertility
- rush-hour traffic — the large number of vehicles that move along roads, travelling to or from work at the beginning and end of the working day
- sacrifice paddock — a grassed area allowed to be grazed completely, to be cultivated and resown later
- sacrificial anode — Chemistry. an anode that is attached to a metal object subject to electrolysis and is decomposed instead of the object.
- safety precaution — a precaution that is taken in order to ensure that something is safe and not dangerous
- san francisco bay — a bay in W California: the harbor of San Francisco; connected with the Pacific by the Golden Gate strait. 50 miles (80 km) long; 3–12 miles (5–19 km) wide.
- scarlet firethorn — a Eurasian evergreen, thorny shrub, Pyracantha coccinea, of the rose family, having white, hairy flower clusters and bright red berries.
- self-appreciation — gratitude; thankful recognition: They showed their appreciation by giving him a gold watch.
- self-confirmation — the act of confirming.
- self-consecration — the act of setting oneself to a task or vocation without ordination by others or by a religious body.
- self-conservation — the act of conserving; prevention of injury, decay, waste, or loss; preservation: conservation of wildlife; conservation of human rights.
- self-purification — a natural process of purifying, as the ability of a body of water to rid itself of pollutants.
- self-renunciation — renunciation of one's own will, interests, etc.
- set one's cap for — a close-fitting covering for the head, usually of soft supple material and having no visor or brim.
- significant other — Sociology. a person, as a parent or peer, who has great influence on one's behavior and self-esteem.
- sister of charity — a member of one of several congregations of sisters founded in 1634 by St. Vincent de Paul.
- south west africa — a former name of Namibia.
- south-west africa — a former name of Namibia.
- sports facilities — places and things for doing sports
- standard function — a subprogram provided by a translator that carries out a task, for example the computation of a mathematical function, such as sine, square root, etc
- stock certificate — a certificate evidencing ownership of one or more shares of stock in a corporation.
- sufficient reason — the principle that nothing happens by pure chance, but that an explanation must always be available
- surface condenser — a device condensing steam or vapor by passing it over a cool surface.
- sword of damocles — Damocles (def 2).
- teaching software — computer software for use in providing online education
- the bag of tricks — every device; everything
- the carboniferous — the Carboniferous period or rock system
- the confederation — the original 13 states of the United States of America constituted under the Articles of Confederation and superseded by the more formal union established in 1789
- the factory floor — all the workers in a factory
- the rann of kutch — an extensive salt waste in W central India, and S Pakistan: consists of the Great Rann in the north and the Little Rann in the southeast; seasonal alternation between marsh and desert; some saltworks. In 1968 an international tribunal awarded about 10 per cent of the border area to Pakistan. Area: 23 000 sq km (9000 sq miles)
- thiosulfuric acid — an acid, H 2 S 2 O 3 , that may be regarded as sulfuric acid with one oxygen atom replaced by sulfur.