19-letter words containing a, e, c, i
- national characters — (character) Characters with accents and other diacritical marks that are used in certain written languages (that are based on the Roman alphabet) but not in others, particularly not in English. A standard list is ISO Latin 1.
- national convention — French History. the legislature of France 1792–95.
- national serviceman — a soldier undertaking compulsory military service
- natural killer cell — a small killer cell that destroys virus-infected cells or tumor cells without activation by an immune system cell or antibody.
- neats vs. scruffies — (artificial intelligence, jargon) The label used to refer to one of the continuing holy wars in artificial intelligence research. This conflict tangles together two separate issues. One is the relationship between human reasoning and AI; "neats" tend to try to build systems that "reason" in some way identifiably similar to the way humans report themselves as doing, while "scruffies" profess not to care whether an algorithm resembles human reasoning in the least as long as it works. More importantly, neats tend to believe that logic is king, while scruffies favour looser, more ad-hoc methods driven by empirical knowledge. To a neat, scruffy methods appear promiscuous, successful only by accident and not productive of insights about how intelligence actually works; to a scruffy, neat methods appear to be hung up on formalism and irrelevant to the hard-to-capture "common sense" of living intelligences.
- necessary condition — prerequisite
- negative income tax — a system of income subsidy through which persons having less than a certain annual income receive money from the government rather than pay taxes to it.
- negative resistance — a characteristic of certain electronic components in which an increase in the applied voltage increases the resistance, producing a proportional decrease in current
- neighbourhood watch — a scheme under which members of a community agree together to take responsibility for keeping an eye on each other's property, as a way of preventing crime
- neuropathologically — In a neuropathologic way.
- neuropsychodynamics — The theoretical synthesis of neuroscience and psychodynamics.
- neville chamberlain — (Arthur) Neville, 1869–1940, British statesman: prime minister 1937–40.
- new zealand spinach — a plant, Tetragonia tetragonioides, of warm regions, cultivated for its edible leaves, eaten as a vegetable.
- newtonian mechanics — the branch of mechanics that is based on Newton's laws of motion and that is applicable to systems that are so large that Planck's constant can be regarded as negligibly small (distinguished from quantum mechanics).
- newtonian telescope — a reflecting telescope in which a mirror or reflecting prism is mounted on the axis near the eyepiece so that the image may be viewed from outside the telescope tube at right angles to the axis.
- niccolo machiavelli — Niccolò di Bernardo [neek-kaw-law dee ber-nahr-daw] /ˌnik kɔˈlɔ di bɛrˈnɑr dɔ/ (Show IPA), 1469–1527, Italian statesman, political philosopher, and author.
- nicolaus copernicus — Nicolaus [nik-uh-ley-uh s] /ˌnɪk əˈleɪ əs/ (Show IPA), (Mikolaj Kopernik) 1473–1543, Polish astronomer who promulgated the now accepted theory that the earth and the other planets move around the sun (the Copernican System)
- no strings attached — without conditions
- no-write allocation — (memory management) A cache policy where only processor reads are cached, thus avoiding the need for write-back or write-through.
- non-confidentiality — spoken, written, acted on, etc., in strict privacy or secrecy; secret: a confidential remark.
- nonmaterial culture — the aggregate of values, mores, norms, etc., of a society; the ideational structure of a culture that provides the values and meanings by which it functions.
- north pacific ocean — the northern part of the Pacific Ocean, extending from the equator to the Arctic Ocean.
- northwest ordinance — the act of Congress in 1787 providing for the government of the Northwest Territory and setting forth the steps by which its subdivisions might become states.
- not care/give a fig — If you say that someone doesn't care a fig or doesn't give a fig about something, you are emphasizing that they think it is unimportant or that they are not interested in it.
- nuclear disarmament — the gradual reduction and eventual elimination of all nuclear weapons in the world
- occupational health — Occupational health is the branch of medicine that deals with the health of people in their workplace or in relation to their job.
- off-highway vehicle — An off-highway vehicle is a vehicle, such as one used for construction or agriculture, that is intended for use on steep or uneven ground.
- office-block ballot — a ballot on which the candidates are listed alphabetically, with or without their party designations, in columns under the office for which they were nominated.
- olive-backed thrush — Swainson's thrush.
- on cue/as if on cue — If you say that something happened on cue or as if on cue, you mean that it happened just when it was expected to happen, or just at the right time.
- on no consideration — for no reason whatsoever; never
- once in a blue moon — very rarely; almost never
- operations director — a director or senior manager who oversees the efficiency of business operations
- operations research — the analysis, usually involving mathematical treatment, of a process, problem, or operation to determine its purpose and effectiveness and to gain maximum efficiency.
- optical 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)
- optical mark reader — (hardware) (OMR) A special scanning device that can read carefully placed pencil marks on specially designed documents. OMR is frequenty used in forms, questionnaires, and answer-sheets.
- orthopaedic surgeon — a surgeon specializing in the branch of surgery concerned with disorders of the spine and joints and the repair of deformities of these parts
- orthopaedic surgery — surgery concerned with disorders of the spine and joints and the repair of deformities of these parts
- over-centralization — the act or fact of centralizing; fact of being centralized.
- over-commercialized — to make commercial in character, methods, or spirit.
- overhead projection — the projection (using an overhead projector) of an enlarged image of a transparency onto a surface above and behind the person using it
- oxidation-reduction — a chemical reaction between two substances in which one substance is oxidized and the other reduced.
- palisade parenchyma — the upper layer of ground tissue in a leaf, consisting of elongated cells beneath and perpendicular to the upper epidermis and constituting the primary area of photosynthesis.
- pancreatic fibrosis — cystic fibrosis.
- parachute spinnaker — a very large spinnaker used on a racing yacht.
- paradichlorobenzene — a white, crystalline, volatile, water-insoluble solid, C 6 H 4 Cl 2 , of the benzene series, having a penetrating odor: used chiefly as a moth repellent.
- parallactic ellipse — the apparent ellipse, as seen against the background of more distant stars, described annually by a nearby star because of the earth's orbital motion around the sun. Compare parallax (def 2).
- parallel processing — extending in the same direction, equidistant at all points, and never converging or diverging: parallel rows of trees.
- parallel projection — a projection from one plane to a second plane in which the lines joining points on the first plane and corresponding images are parallel.
- parametric equation — one of two or more equations expressing the location of a point on a curve or surface by determining each coordinate separately.