18-letter words containing a, c, p
- cathode dark space — Crookes dark space.
- cellular telephone — a mobile phone
- central projection — a projection of one plane onto a second plane such that a point on the first plane and its image on the second plane lie on a straight line through a fixed point not on either plane.
- cepheid (variable) — any of a class of pulsating, yellow, supergiant stars whose brightness varies in regular periods: from the period-luminosity relation, the distance of such a star can be determined
- chagos archipelago — group of islands in the Indian Ocean 1,180 mi (1,899 km) northeast of Mauritius, comprising the British Indian Ocean Territory: chief island, Diego Garcia
- championship point — a point that would decide the winner of a match that would decide the championship
- change one's spots — to reform one's character
- changement de pied — a jump in which the dancer's feet are reversed from the starting position.
- character graphics — ASCII art
- checkpoint charlie — a crossing between East and West Berlin during the Cold War
- chemical potential — a thermodynamic function of a substance in a system that is the partial differential of the Gibbs function of the system with respect to the number of moles of the substance
- chemical pregnancy — a pregnancy that is confirmed by a pregnancy test but not by clinical signs and terminates before clinical signs can be observed.
- chloroacetophenone — a white, crystalline, water-insoluble, poisonous solid, C 8 H 7 ClO, used in solution as a tear gas. Abbreviation: CN.
- christine de pisan — ?1364–?1430, French poet and prose writer, born in Venice. Her works include ballads, rondeaux, lays, and a biography of Charles V of France
- christmas shopping — shopping especially for Christmas presents, but also for Christmas food and drink, and all the other things required over the Christmas period.
- chromatic printing — printing from blocks or types inked with various colours
- chromolithographer — One engaged in chromolithography.
- chromolithographic — Pertaining to, or made by, chromolithography.
- chronostratigraphy — The branch of geology concerned with establishing the absolute ages of strata.
- citizenship papers — the document stating that a naturalized person has been formally declared a citizen
- claustrophobically — In a claustrophobic way.
- clean up one's act — to start to behave in a responsible manner
- cleopatra's needle — either of two Egyptian obelisks, originally set up at Heliopolis about 1500 bc: one was moved to the Thames Embankment, London, in 1878, the other to Central Park, New York, in 1880
- clinical pathology — the branch of pathology dealing with the study of disease and disease processes by means of chemical, microscopic, and serologic examinations.
- closed corporation — a corporation the stock of which is owned by a small number of persons and is rarely traded on the open market
- closed scholarship — a scholarship for which only certain people, such as those from a particular school or with a particular surname, are eligible
- cobalt violet deep — a medium to strong purple color.
- cock-a-leekie soup — a soup made from a fowl boiled with leeks
- color transparency — a positive color image photographically produced on transparent film or glass and viewed by transmitted light, usually by projection.
- colour photography — the art or process of taking and developing photographs in colour
- colour temperature — the temperature of a black-body radiator at which it would emit radiation of the same chromaticity as the light under consideration
- combined operation — a military operation carried out jointly by allied forces
- come the raw prawn — to attempt deception
- commando operation — a major operation for treatment of cancer of the head and neck, involving removal of many facial structures and subsequent surgical reconstruction
- community hospital — (in the US) a local hospital
- compact video disc — a compact laser disc that plays both pictures and sound
- companion planting — the cultivation of different types of plants in close proximity so as to benefit each other, as planting a deer-repellent plant in a flower garden.
- comparative method — a body of procedures and criteria used by linguists to determine whether and how two or more languages are related and to reconstruct forms of their hypothetical parent language.
- comparison shopper — an employee of a retail store hired to visit competing stores in order to gather information regarding styles, quality, prices, etc., of merchandise offered by competitors.
- compartmentalizing — Present participle of compartmentalize.
- compassion fatigue — the inability to react sympathetically to a crisis, disaster, etc, because of overexposure to previous crises, disasters, etc
- compassionlessness — The quality, state, or condition of being compassionless; uncompassion.
- compensation award — an amount of money awarded as compensation in a court case
- compensation order — (in Britain) the requirement of a court that an offender pay compensation for injury, loss, or damage resulting from an offence, either in preference to or as well as a fine
- compensation point — the concentration of atmospheric carbon dioxide at which the rate of carbon dioxide uptake by a photosynthesizing plant is exactly balanced by its rate of carbon dioxide release in respiration and photorespiration
- complementarianism — The doctrine that genders in a society should have complementary roles.
- complementary base — either of the nucleotide bases linked by a hydrogen bond on opposite strands of DNA or double-stranded RNA: guanine is the complementary base of cytosine, and adenine is the complementary base of thymine in DNA and of uracil in RNA.
- complementary gene — one of a pair of genes, each from different loci, that together are required for the expression of a certain characteristic
- complexity measure — (algorithm) A quantity describing the complexity of a computation.
- compliance officer — a specialist, usually a lawyer, employed by a financial group operating in a variety of fields and for multiple clients to ensure that no conflict of interest arises and that all obligations and regulations are complied with