Me·chan·ic·al a.
 1. Pertaining to, governed by, or in accordance with, mechanics, or the laws of motion; pertaining to the quantitative relations of force and matter on a macroscopic scale, as distinguished from mental, vital, chemical, electrical, electronic, atomic etc.; as, mechanical principles; a mechanical theory; especially, using only the interactions of solid parts against each other; as mechanical brakes, in contrast to hydraulic brakes.
 2. Of or pertaining to a machine or to machinery or tools; made or formed by a machine or with tools; as, mechanical precision; mechanical products.
    We have also divers mechanical arts.   --Bacon.
 3. Done as if by a machine; uninfluenced by will or emotion; proceeding automatically, or by habit, without special intention or reflection; as, mechanical singing; mechanical verses; mechanical service.
 4. Made and operated by interaction of forces without a directing intelligence; as, a mechanical universe.
 5. Obtained by trial, by measurements, etc.; approximate; empirical. See the 2d Note under Geometric.
 Mechanical effect, effective power; useful work exerted, as by a machine, in a definite time.
 Mechanical engineering. See the Note under Engineering.
 Mechanical maneuvers Mil., the application of mechanical appliances to the mounting, dismounting, and moving of artillery. --Farrow.
 Mechanical philosophy, the principles of mechanics applied to the investigation of physical phenomena.
 Mechanical powers, certain simple instruments, such as the lever and its modifications (the wheel and axle and the pulley), the inclined plane with its modifications (the screw and the wedge), which convert a small force acting through a great space into a great force acting through a small space, or vice versa, and are used separately or in combination.
 Mechanical solution Math., a solution of a problem by any art or contrivance not strictly geometrical, as by means of the ruler and compasses, or other instruments.


 Pow·er, n.
 1. Ability to act, regarded as latent or inherent; the faculty of doing or performing something; capacity for action or performance; capability of producing an effect, whether physical or moral: potency; might; as, a man of great power; the power of capillary attraction; money gives power. “One next himself in power, and next in crime.”
 2. 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 power of fancy.”
 3. Capacity of undergoing or suffering; fitness to be acted upon; susceptibility; -- called also passive power; as, great power of endurance.
    Power, then, is active and passive; faculty is active power or capacity; capacity is passive power.   --Sir W. Hamilton.
 4. The exercise of a faculty; the employment of strength; the exercise of any kind of control; influence; dominion; sway; command; government.
    Power is no blessing in itself but when it is employed to protect the innocent.   --Swift.
 5. 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. “The powers of darkness.”
    And the powers of the heavens shall be shaken.   --Matt. xxiv. 29.
 6. A military or naval force; an army or navy; a great host.
 Never such a power . . .
 Was levied in the body of a land.   --Shak.
 7. A large quantity; a great number; as, a power o░ good things. [Colloq.]
 8. Mech. (a) 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.
 Note: ☞ The English unit of power used most commonly is the horse power. See Horse power.
 (b) A mechanical agent; that from which useful mechanical energy is derived; as, water power; steam power; hand power, etc. (c) 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.
 Note: ☞ This use in mechanics, of power as a synonym for force, is improper and is becoming obsolete.
 (d) A machine acted upon by an animal, and serving as a motor to drive other machinery; as, a dog power.
 Note: ☞ Power is used adjectively, denoting, driven, or adapted to be driven, by machinery, and not actuated directly by the hand or foot; as, a power lathe; a power loom; a power press.
 9. Math. 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.
 10. Metaph. 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.
    The guiltiness of my mind, the sudden surprise of my powers, drove the grossness . . . into a received belief.   --Shak.
 11. 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.
 12. Law An authority enabling a person to dispose of an interest vested either in himself or in another person; ownership by appointment.
 13. Hence, vested authority to act in a given case; as, the business was referred to a committee with power.
 Note: ☞ 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.
 Mechanical powers. See under Mechanical.
 Power loom, or Power press. See Def. 8 (d), note.
 Power of attorney. See under Attorney.
 Power of a point (relative to a given curve) Geom., 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, x² + y² - 100 is the power of the point x, y, relative to the circle x² + y² - 100 = 0.

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 Wedge n.
 1. A piece of metal, or other hard material, thick at one end, and tapering to a thin edge at the other, used in splitting wood, rocks, etc., in raising heavy bodies, and the like. It is one of the six elementary machines called the mechanical powers.  See Illust. of Mechanical powers, under Mechanical.
 2. Geom. A solid of five sides, having a rectangular base, two rectangular or trapezoidal sides meeting in an edge, and two triangular ends.
 3. A mass of metal, especially when of a wedgelike form.  “Wedges of gold.”
 4. Anything in the form of a wedge, as a body of troops drawn up in such a form.
 In warlike muster they appear,
 In rhombs, and wedges, and half-moons, and wings.   --Milton.
 5. The person whose name stands lowest on the list of the classical tripos; -- so called after a person (Wedgewood) who occupied this position on the first list of 1828.  [Cant, Cambridge Univ., Eng.]
 Fox wedge. Mach. & Carpentry See under Fox.
 Spherical wedge Geom., the portion of a sphere included between two planes which intersect in a diameter.


 Wheel n.
 1. A circular frame turning about an axis; a rotating disk, whether solid, or a frame composed of an outer rim, spokes or radii, and a central hub or nave, in which is inserted the axle, -- used for supporting and conveying vehicles, in machinery, and for various purposes; as, the wheel of a wagon, of a locomotive, of a mill, of a watch, etc.
 The gasping charioteer beneath the wheel
 Of his own car.   --Dryden.
 2. Any instrument having the form of, or chiefly consisting of, a wheel.  Specifically: --
 (a) A spinning wheel.  See under Spinning.
 (b) An instrument of torture formerly used.
    His examination is like that which is made by the rack and wheel.   --Addison.
 Note: ☞ This mode of torture is said to have been first employed in Germany, in the fourteenth century. The criminal was laid on a cart wheel with his legs and arms extended, and his limbs in that posture were fractured with an iron bar. In France, where its use was restricted to the most atrocious crimes, the criminal was first laid on a frame of wood in the form of a St. Andrew's cross, with grooves cut transversely in it above and below the knees and elbows, and the executioner struck eight blows with an iron bar, so as to break the limbs in those places, sometimes finishing by two or three blows on the chest or stomach, which usually put an end to the life of the criminal, and were hence called coups-de-grace -- blows of mercy. The criminal was then unbound, and laid on a small wheel, with his face upward, and his arms and legs doubled under him, there to expire, if he had survived the previous treatment.
 (c) Naut. A circular frame having handles on the periphery, and an axle which is so connected with the tiller as to form a means of controlling the rudder for the purpose of steering.
 (d) Pottery A potter's wheel.  See under Potter.
    Then I went down to the potter's house, and, behold, he wrought a work on the wheels.   --Jer. xviii. 3.
 Turn, turn, my wheel! This earthen jar
 A touch can make, a touch can mar.   --Longfellow.
 (e) Pyrotechny A firework which, while burning, is caused to revolve on an axis by the reaction of the escaping gases.
 (f) Poetry The burden or refrain of a song.
 Note: ☞ “This meaning has a low degree of authority, but is supposed from the context in the few cases where the word is found.”
 You must sing a-down a-down,
 An you call him a-down-a.
 O, how the wheel becomes it!   --Shak.
 3. A bicycle or a tricycle; a velocipede.
 4. A rolling or revolving body; anything of a circular form; a disk; an orb.
 5. A turn revolution; rotation; compass.
    According to the common vicissitude and wheel of things, the proud and the insolent, after long trampling upon others, come at length to be trampled upon themselves.   --South.
    [He] throws his steep flight in many an aery wheel.   --Milton.
 A wheel within a wheel, or Wheels within wheels, a complication of circumstances, motives, etc.
 Balance wheel. See in the Vocab.
 Bevel wheel, Brake wheel, Cam wheel, Fifth wheel, Overshot wheel, Spinning wheel, etc. See under Bevel, Brake, etc.
 Core wheel. Mach. (a) A mortise gear. (b) A wheel having a rim perforated to receive wooden cogs; the skeleton of a mortise gear.
 Measuring wheel, an odometer, or perambulator.
 Wheel and axle Mech., one of the elementary machines or mechanical powers, consisting of a wheel fixed to an axle, and used for raising great weights, by applying the power to the circumference of the wheel, and attaching the weight, by a rope or chain, to that of the axle. Called also axis in peritrochio, and perpetual lever, -- the principle of equilibrium involved being the same as in the lever, while its action is continuous.  See Mechanical powers, under Mechanical.
 Wheel animal, or Wheel animalcule Zool., any one of numerous species of rotifers having a ciliated disk at the anterior end.
 Wheel barometer. Physics See under Barometer.
 Wheel boat, a boat with wheels, to be used either on water or upon inclined planes or railways.
 Wheel bug Zool., a large North American hemipterous insect (Prionidus cristatus) which sucks the blood of other insects. So named from the curious shape of the prothorax.
 Wheel carriage, a carriage moving on wheels.
 Wheel chains, or Wheel ropes Naut., the chains or ropes connecting the wheel and rudder.
 Wheel cutter, a machine for shaping the cogs of gear wheels; a gear cutter.
 Wheel horse, one of the horses nearest to the wheels, as opposed to a leader, or forward horse; -- called also wheeler.
 Wheel lathe, a lathe for turning railway-car wheels.
 Wheel lock. (a) A letter lock.  See under Letter. (b) A kind of gunlock in which sparks were struck from a flint, or piece of iron pyrites, by a revolving wheel. (c) A kind of brake a carriage.
 Wheel ore Min., a variety of bournonite so named from the shape of its twin crystals.  See Bournonite.
 Wheel pit Steam Engine, a pit in the ground, in which the lower part of the fly wheel runs.
 Wheel plow, or Wheel plough, a plow having one or two wheels attached, to render it more steady, and to regulate the depth of the furrow.
 Wheel press, a press by which railway-car wheels are forced on, or off, their axles.
 Wheel race, the place in which a water wheel is set.
 Wheel rope Naut., a tiller rope.  See under Tiller.
 Wheel stitch Needlework, a stitch resembling a spider's web, worked into the material, and not over an open space. --Caulfeild & S. (Dict. of Needlework).
 Wheel tree Bot., a tree (Aspidosperma excelsum) of Guiana, which has a trunk so curiously fluted that a transverse section resembles the hub and spokes of a coarsely made wheel.  See Paddlewood.
 Wheel urchin Zool., any sea urchin of the genus Rotula having a round, flat shell.
 Wheel window Arch., a circular window having radiating mullions arranged like the spokes of a wheel.  Cf. Rose window, under Rose.