| Powassan encephalitis | <neurology, paediatrics> An acute disease of children varying clinically from undifferentiated febrile illness to encephalitis. It is caused by the Powassan virus, a member of the Flaviviridae family, and transmitted by ixodid ticks; most frequently seen in Canada. (05 Mar 2000) |
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| Powassan virus | <virology> A virus of the genus Flavivirus (family Flaviviridae), transmitted by ixodid ticks and causing Powassan encephalitis in children; also capable of producing meningoencephalomyelitis in rabbits and children. Origin: Powassan, Canada, where first isolated (05 Mar 2000) |
| powder | 1. The fine particles to which any dry substance is reduced by pounding, grinding, or triturating, or into which it falls by decay; dust. "Grind their bones to powder small." (Shak) 2. An explosive mixture used in gunnery, blasting, etc.; gunpowder. See Gunpowder. Atlas powder, Baking powder, etc. See Atlas, Baking, etc. Powder down, a boy formerly employed on war vessels to carry powder; a powder boy. Powder post. See Dry rot, under Dry. Powder puff. See Puff. Origin: OE. Poudre, pouldre, F. Poudre, OF. Also poldre, puldre, L. Pulvis, pulveris: cf. Pollen fine flour, mill dust, E. Pollen. Cf. Polverine, Pulverize. 1. To be reduced to powder; to become like powder; as, some salts powder easily. 2. To use powder on the hair or skin; as, she paints and powders. Source: Websters Dictionary (01 Mar 1998) |
| powder-posted | Affected with dry rot; reduced to dust by rot. See Dry rot, under Dry. (01 Mar 1998) |
| powdered gold | Gold formed by atomizing or by chemical precipitation, lightly precondensed, and wrapped with gold foil so as to form pellets. (05 Mar 2000) |
| powdered ipecac | A form of ipecac used in the preparation of ipecac syrup (05 Mar 2000) |
| powdered opium | Dried and finely powdered opium containing 10% morphine. (05 Mar 2000) |
| powdered stomach | The dried and powdered defatted wall of the stomach of the hog, Sus scrofa; it contains thermolabile factors including native vitamin B12 and intrinsic factor; has been used in the treatment of pernicious anaemia. (05 Mar 2000) |
| powders | Substances made up of an aggregation of small particles, as that obtained by grinding or trituration of a solid drug. In pharmacy it is a form in which substances are administered. (12 Dec 1998) |
| powen | <zoology> A small British lake whitefish (Coregonus clupeoides, or C. Ferus). Synonym: gwyniad and lake herring. Source: Websters Dictionary (01 Mar 1998) |
| power | 1. Ability, regarded as put forth or exerted; strength, force, or energy in action; as, the power of steam in moving an engine; the power of truth, or of argument, in producing conviction; the power of enthusiasm. The agent exercising an ability to act; an individual invested with authority; an institution, or government, which exercises control; as, the great powers of Europe; hence, often, a superhuman agent; a spirit; a divinity. 2. <psychology> The exertion of a strong influence or control over others in a variety of settings; administrative, social, academic, etc. Mental or moral ability to act; one of the faculties which are possessed by the mind or soul; as, the power of thinking, reasoning, judging, willing, fearing, hoping, etc. 3. <mechanics> The rate at which mechanical energy is exerted or mechanical work performed, as by an engine or other machine, or an animal, working continuously; as, an engine of twenty horse power. Applied force; force producing motion or pressure; as, the power applied at one and of a lever to lift a weight at the other end. 4. <unit> The English unit of power used most commonly is the horse power. See Horse power. 5. <mathematics> The product arising from the multiplication of a number into itself; as, a square is the second power, and a cube is third power, of a number. 6. <optics> The degree to which a lens, mirror, or any optical instrument, magnifies; in the telescope, and usually in the microscope, the number of times it multiplies, or augments, the apparent diameter of an object; sometimes, in microscopes, the number of times it multiplies the apparent surface. 7. Power may be predicated of inanimate agents, like the winds and waves, electricity and magnetism, gravitation, etc, or of animal and intelligent beings; and when predicated of these beings, it may indicate physical, mental, or moral ability or capacity. 8. <geometry> Power of a point (relative to a given curve), the result of substituting the coordinates of any point in that expression which being put equal to zero forms the equation of the curve; as, x^2 + y^2 - 100 is the power of the point x, y, relative to the circle x^2 + y^2 - 100 = 0. Origin: OE. Pouer, poer, OF. Poeir, pooir, F. Pouvoir, n. & v, fr. LL. Potere, for L. Posse, potesse, to be able, to have power. See Possible, Potent, and cf. Posse comitatus. Source: Websters Dictionary (04 Jul 1999) |
| power failure | Synonym: pump failure. (05 Mar 2000) |
| power injector | An injector for rapid contrast medium injection in angiography or computed tomography. (05 Mar 2000) |
| power plants | Units that convert some form of energy into electrical energy, such as hydroelectric or steam-generating stations, diesel-electric engines in locomotives, or nuclear power plants. (12 Dec 1998) |
| power point | In dentistry, the vertical dimension at which the greatest masticatory force may be registered. (05 Mar 2000) |