| 释义 |
spiral
spi·ral S0645800 (spī′rəl)n.1. a. A curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point.b. A three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis; a helix.c. Something having the form of such a curve: a spiral of black smoke.2. Printing A spiral binding.3. The course or flight path of an object rotating on its longitudinal axis.4. A continuously accelerating increase or decrease: the wage-price spiral.adj.1. Of or resembling a spiral.2. Circling around a center at a continuously increasing or decreasing distance.3. Coiling around an axis in a constantly changing series of planes; helical.4. Printing Relating to or having a spiral binding: a spiral notebook.v. spi·raled, spi·ral·ing, spi·rals also spi·ralled or spi·ral·ling v.intr.1. To take a spiral form or course.2. To rise or fall with steady acceleration.v.tr. To cause to take a spiral form or course.
[Medieval Latin spīrālis, of a spiral, from Latin spīra, coil; see spire2.]
spi·ral′i·ty (spī-răl′ĭ-tē) n.spi′ral·ly adv.spiral (ˈspaɪərəl) n1. (Mathematics) geometry one of several plane curves formed by a point winding about a fixed point at an ever-increasing distance from it. Polar equation of Archimedes spiral: r = aθ; of logarithmic spiral: log r = aθ; of hyperbolic spiral: rθ = a, (where a is a constant)2. (Mathematics) another name for helix13. something that pursues a winding, usually upward, course or that displays a twisting form or shape4. (Aeronautics) a flight manoeuvre in which an aircraft descends describing a helix of comparatively large radius with the angle of attack within the normal flight range. Compare spin165. (Economics) economics a continuous upward or downward movement in economic activity or prices, caused by interaction between prices, wages, demand, and productionadjhaving the shape of a spiralvb, -rals, -ralling or -ralled, -rals, -raling or -raled6. to assume or cause to assume a spiral course or shape7. (intr) to increase or decrease with steady acceleration: wages and prices continue to spiral. [C16: via French from Medieval Latin spīrālis, from Latin spīra a coil; see spire2] ˈspirally advspi•ral (ˈspaɪ rəl)
n., adj., v. -raled, -ral•ing (esp. Brit.) -ralled, -ral•ling. n. 1. a plane curve generated by a point moving around a fixed point while constantly receding from or approaching it. 2. a helix. 3. a single circle or ring of a spiral or helical curve or object. 4. a spiral or helical object, formation, or form. 5. a football thrown or kicked so that the ball turns on its longer axis as it flies through the air. 6. a continuous increase or decrease in wages, prices, etc. adj. 7. of or of the nature of a spire or coil. 8. bound with a spiral binding; spiral-bound: a spiral notebook. v.i. 9. to take a spiral form or course. 10. to rise or fall steadily. [1545–55; < Medieval Latin spīrālis= Latin spīr(a) coil (< Greek speîra; compare spire2) + -ālis -al1] spi′ral•ly, adv. spiral
Past participle: spiralled
Gerund: spiralling
| Present |
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| I spiral | | you spiral | | he/she/it spirals | | we spiral | | you spiral | | they spiral |
| Preterite |
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| I spiralled | | you spiralled | | he/she/it spiralled | | we spiralled | | you spiralled | | they spiralled |
| Present Continuous |
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| I am spiralling | | you are spiralling | | he/she/it is spiralling | | we are spiralling | | you are spiralling | | they are spiralling |
| Present Perfect |
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| I have spiralled | | you have spiralled | | he/she/it has spiralled | | we have spiralled | | you have spiralled | | they have spiralled |
| Past Continuous |
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| I was spiralling | | you were spiralling | | he/she/it was spiralling | | we were spiralling | | you were spiralling | | they were spiralling |
| Past Perfect |
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| I had spiralled | | you had spiralled | | he/she/it had spiralled | | we had spiralled | | you had spiralled | | they had spiralled |
| Future |
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| I will spiral | | you will spiral | | he/she/it will spiral | | we will spiral | | you will spiral | | they will spiral |
| Future Perfect |
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| I will have spiralled | | you will have spiralled | | he/she/it will have spiralled | | we will have spiralled | | you will have spiralled | | they will have spiralled |
| Future Continuous |
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| I will be spiralling | | you will be spiralling | | he/she/it will be spiralling | | we will be spiralling | | you will be spiralling | | they will be spiralling |
| Present Perfect Continuous |
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| I have been spiralling | | you have been spiralling | | he/she/it has been spiralling | | we have been spiralling | | you have been spiralling | | they have been spiralling |
| Future Perfect Continuous |
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| I will have been spiralling | | you will have been spiralling | | he/she/it will have been spiralling | | we will have been spiralling | | you will have been spiralling | | they will have been spiralling |
| Past Perfect Continuous |
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| I had been spiralling | | you had been spiralling | | he/she/it had been spiralling | | we had been spiralling | | you had been spiralling | | they had been spiralling |
| Conditional |
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| I would spiral | | you would spiral | | he/she/it would spiral | | we would spiral | | you would spiral | | they would spiral |
| Past Conditional |
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| I would have spiralled | | you would have spiralled | | he/she/it would have spiralled | | we would have spiralled | | you would have spiralled | | they would have spiralled |
Thesaurus| Noun | 1. |  spiral - a plane curve traced by a point circling about the center but at increasing distances from the centercurve, curved shape - the trace of a point whose direction of motion changes | | 2. |  spiral - a curve that lies on the surface of a cylinder or cone and cuts the element at a constant anglehelixcurve, curved shape - the trace of a point whose direction of motion changesdouble helix - a pair of parallel helices intertwined about a common axis; "the shape of the DNA molecule is a double helix" | | 3. | spiral - a continuously accelerating change in the economyeconomic process - any process affecting the production and development and management of material wealthinflationary spiral - an episode of inflation in which prices and wages increase at an increasing rate and currency rapidly loses valuedeflationary spiral - an episode of deflation in which prices and wages decrease at an increasing rate and currency gains in value | | 4. |  spiral - ornament consisting of a curve on a plane that winds around a center with an increasing distance from the centervolutedecoration, ornament, ornamentation - something used to beautify | | 5. |  spiral - a structure consisting of something wound in a continuous series of loops; "a coil of rope"coil, helix, volute, whorlhank - a coil of rope or wool or yarnstructure, construction - a thing constructed; a complex entity constructed of many parts; "the structure consisted of a series of arches"; "she wore her hair in an amazing construction of whirls and ribbons" | | 6. | spiral - flying downward in a helical path with a large radiusrotary motion, rotation - the act of rotating as if on an axis; "the rotation of the dancer kept time with the music" | | Verb | 1. | spiral - to wind or move in a spiral course; "the muscles and nerves of his fine drawn body were coiling for action"; "black smoke coiling up into the sky"; "the young people gyrated on the dance floor"coil, gyrateturn - change orientation or direction, also in the abstract sense; "Turn towards me"; "The mugger turned and fled before I could see his face"; "She turned from herself and learned to listen to others' needs" | | 2. | spiral - form a spiral; "The path spirals up the mountain"curve, wind, twist - extend in curves and turns; "The road winds around the lake"; "the path twisted through the forest" | | 3. | spiral - move in a spiral or zigzag coursecorkscrewturn - change orientation or direction, also in the abstract sense; "Turn towards me"; "The mugger turned and fled before I could see his face"; "She turned from herself and learned to listen to others' needs" | | Adj. | 1. |  spiral - in the shape of a coil coiling, helical, spiraling, volute, voluted, whorled, turbinatecoiled - curled or wound (especially in concentric rings or spirals); "a coiled snake ready to strike"; "the rope lay coiled on the deck" |
spiraladjective1. coiled, winding, corkscrew, circular, scrolled, whorled, helical, cochlear, voluted, cochleate (Biology) a spiral staircasenoun1. coil, helix, corkscrew, whorl, screw, gyre (literary), curlicue, volute Larks were rising in spirals from the ridge.verb1. coil, wind, twist, snake, twirl Smoke spiralled from a joss stick.2. soar, rise, escalate, climb, rocket, shoot up a spiralling trend of violencespiral downwards decline, fall, drop, sink, shrink, decrease, deteriorate, fall off, dwindle, wane, ebb House prices will continue to spiral downwards.spiralverbTo move or proceed on a repeatedly curving course:coil, corkscrew, curl, entwine, meander, snake, twine, twist, weave, wind, wreathe.Translationsspiral (ˈspaiərəl) adjective1. coiled round like a spring, with each coil the same size as the one below. a spiral staircase. 盤旋的 盘旋的2. winding round and round, usually tapering to a point. a spiral shell. 螺旋形的 螺旋形的 noun1. an increase or decrease, or rise or fall, becoming more and more rapid (eg in prices). 不斷上升或下降 不断上升或下降2. a spiral line or object. A spiral of smoke rose from the chimney. 盤旋(形) 盘旋（形） verb – past tense, past participle ˈspiralled , (American) ˈspiraled – to go or move in a spiral, especially to increase more and more rapidly. Prices have spiralled in the last six months. 螺旋上升 螺旋上升ˈspirally adverb 呈螺旋形地 呈螺旋形地spiral
death spiral1. In aviation, a dangerous downward cork-screw maneuver of a disabled or uncontrollable aircraft that often leads to a crash. Also called a "spiral dive." The pilot, unaware of the plane's slight roll in the cloud bank, only realized he was in a death spiral when it was too late to overcome the dive.2. In pairs figure skating, a maneuver in which the male partner, in a pivot position, spins the female partner with one hand in a wide circle with her body nearly parallel to the ground. The two pulled off an amazing death spiral—her head looked as though it were about to touch the ice at one point!3. In insurance (especially health insurance), a plan in which costs rapidly increase over time due to policyholders with a lower risk opting out of the policy, forcing those dependent on it to pay higher premiums, thus prompting more low-risk policy holders to opt out and further drive up costs, and so on. I purchased my health insurance plan as a means to afford my medicine, but it turned into a death spiral when employers started offering cheaper, barebones plans that the majority of people were quick to switch to.4. In finance, a loan given by investors to a company in exchange for convertible bonds, which can then be converted to common stock at prices lower than the market value, causing overall share prices to fall and more bondholders to trade their stock for equity, ultimately leading to a collapse of the company's stock worth altogether. To keep his company afloat, Tom was forced to take a loan that ultimately proved a death spiral, leading him to close the business anyway.5. Any situation in which a series of events or actions, especially as a consequence of one another, ultimately lead to a point of ruin, failure, or destruction. With the recent allegations of drug abuse, corruption charges, and controversial remarks about minorities, the long-time senator now seems locked into an irreversible death spiral.See also: death, spiralspiral down1. To travel down (something) in a twirling or spiraling motion. After the second engine went dead, the plane started spiraling down to the ground. I pulled the plug and watched the water spiral down the drain.2. Of some measurement or value, to decrease very rapidly. The company's stock prices have spiraled down since the CEO's arrest, dropping nearly 18 points in two days. As the sun set the temperature began spiraling down, so I knew we needed to find shelter soon.See also: down, spiralspiral upTo move, proceed, or lead up in a spiral path or motion. The ornate staircase spiraled up to the second floor. The dust spiraled up into the air in a small whirlwind.See also: spiral, upspiral downto descend in a spiral path. The ancient trail spiraled down the mountain peak. A path spiraled down and at the bottom was a small refreshment stand.See also: down, spiralspiral upto ascend in a spiral path. The smoke spiraled up to the sky. The trail spiraled up the slope to the top.See also: spiral, upspiral
spiral1. Geometry one of several plane curves formed by a point winding about a fixed point at an ever-increasing distance from it. Polar equation of Archimedes spiral: r = aθ; of logarithmic spiral: log r = aθ; of hyperbolic spiral: rθ = a, (where a is a constant) 2. another name for helix3. a flight manoeuvre in which an aircraft descends describing a helix of comparatively large radius with the angle of attack within the normal flight range 4. Economics a continuous upward or downward movement in economic activity or prices, caused by interaction between prices, wages, demand, and production SpiralRefers to forms that are generated by a continuous curve, traced by a point moving around a fixed point in a fixed plane, while steadily increasing the distance from that point. Spiral a plane curve going around a certain point an infinite number of times and approaching or receding from the point on each circuit. If this point is chosen as the pole of a polar coordinate system, then the spiral is given by a popular equation p = f (φ) such that f (φ + 2π) > f (φ) or f (φ + 2π) < f (φ) for all*. In particular, a spiral is obtained if f (φ) is a monotone increasing or decreasing positive function.  Figure 1. (a) Spiral of Archimedes, (b) logarithmic spiral, (c) Cornu spiral, (d) parabolic spiral, (e) hyperbolic spiral, (f) lituus, (g) si-ci spiral, (h) cochleold
The equation of the spiral of Archimedes (Figure 1 ,a) has the simplest form: ρ = α. In the third century B.C., this spiral was studied by the ancient Greek mathematician Archimedes, in his treatise On Spirals, in connection with the problems of trisecting an angle and squaring the circle. Archimedes found the area bounded by an arc of the spiral extending from the pole to a certain point and by the line joining the pole and this point. This achievement was one of the first examples of the quadrature of a curvilinear region. The spiral of Archimedes is the pedal curve (seePEDAL CURVE) of the involute of a circle. This fact is made use of in certain drawbridge designs in balancing the variable tension of the chain. A cardioid eccentric cam—that is, an eccentric cam bounded by two arcs of Archimedean spirals—transforms uniform rotational motion into uniform translational motion. The distance between diametrically opposite points on the periphery of the cam is constant. The French mathematician P. de Fermat studied the generalized spiral of Archimedes (ρ/α)n = (Φ/2π)m and found the area bounded by an arc of the spiral extending from the pole to a certain point and by the line joining the pole and this point. The equation ρ = aekφ defines the logarithmic, or equiangular, spiral (Figure l,b). The logarithmic spiral intersects all radius vectors drawn from the pole at the same angle α, where cot α = k. This property of the logarithmic spiral is made use of in designing rotary cutters in order to ensure a constant cutting angle. The logarithmic spiral is also encountered in the theory of spiral cases for hydraulic turbines. The theory of gear wheels makes use of the following property: two equal logarithmic spirals rotating about their poles can roll along each other without slipping. Gear trains with variable gear ratios can be obtained in this way. In the stereographic projection of a sphere onto a plane, a logarithmic spiral is the projection of a loxodrome, which is a curve that cuts all meridians at the same angle. The Italian mathematician E. Torricelli determined the length of an arc of a logarithmic spiral: the arc length is proportional to the difference between the lengths of the radius vectors of the end points of the arc; more precisely, the arc length is (ρ2 ρ1))/cos α. The Swiss scientist J. Bernoulli showed that the evolute and caustic of a logarithmic spiral are logarithmic spirals. When a logarithmic spiral is rotated about the pole, the curve obtained is homothetic to the original curve. Under inversion with respect to a circle, a logarithmic spiral is transformed into a logarithmic spiral. Another spiral of practical importance is the Cornu spiral, or clothoid, which is used in the graphic solution of certain problems in diffraction (Figure 1 ,c). The parametric equations of this spiral have the form 
The Cornu spiral is an ideal transition curve for use in railroad tracks, since the spiral’s radius of curvature increases in proportion to the arc length. There exist spirals that are involutes of closed curves. An example is the involute of a circle. The names of some spirals stem from the resemblance of the spirals’ polar equations to the equations of curves in Cartesian coordinates. For example, the parabolic spiral (Figure 1 ,d) has the equation (a – ρ)2 = bφ, and the hyperbolic spiral (Figure l,e) has the equation ρ = α/φ. Other spirals include the lituus (Figure 1 ,f), whose equation is ρ2 = α/Φ, and the si-ci spiral (Figure 1 ,g), whose parametric equations have the form 
where si(t) and ci(i) are known as the sine integral and cosine integral, respectively. The curvature of this spiral is an exponential function of the arc length. Such spirals are used in french curves. Reminiscent of a spiral is the cochleoid (Figure l,h), whose equation is φ = (α sin φ)/φ. This curve passes through the pole an infinite number of times, and each succeeding loop lies within the preceding loop. Spirals are encountered in the study of singularities of differential equations (seeSINGULAR POINT). Space curves that make an infinite number of circuits about an axis, for example, the helix, are also sometimes referred to as spirals. What does it mean when you dream about a spiral?Spiraling, either upward or downward, is often used figuratively to refer to the rapid rise and fall of finances. It may also symbolize flux in weather, health, and employment cycles, to name just a few. It can also simply mean that the dreamer feels things are “spiraling out of control.” spiral[′spī·rəl] (mathematics) A simple curve in the plane which continuously winds about itself either into some point or out from some point. spiralA continuously wound reinforcement in the form of a cylindrical helix.spiralA maneuver in which an airplane descends rapidly in a steeply banked turning flight path. The angle of attack remains within the normal range in a spiral. The aircraft speed tends to increase unless other-wise controlled by actions such as throttling back and/or using airbrakes.spiral
spiral [spi´ral] 1. winding like the thread of a screw; called also helical.2. a winding structure; see also coil and helix.Curschmann's s's coiled fibrils of mucin sometimes found in the sputum of patients with asthma. See also Laënnec's pearls.spi·ral (spī'răl), 1. Coiled; winding around a center like a watch spring; winding and ascending like a wire spring. 2. A structure in the shape of a coil. [Mediev. L. spiralis, fr. G. speira, a coil] spi·ral (spī'răl) 1. Coiled; winding around a center like a watch spring; winding and ascending like a wire spring. 2. A structure in the shape of a coil. [Mediev. L. spiralis, fr. G. speira, a coil]spi·ral (spī'răl) 1. Coiled; winding around a center like a watch spring; winding and ascending like a wire spring. 2. Structure in shape of a coil. [Mediev. L. spiralis, fr. G. speira, a coil]See SPL
SPIRAL
| Acronym | Definition |
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| SPIRAL➣Selected Patient Information Resources in Asian Languages (Tufts University) | | SPIRAL➣Scientific and Public Involvement in Risk Allocations Laboratory (research group; Belgium) | | SPIRAL➣Service Pédagogique Interuniversitaire de Ressources pour l'Autoformation en Langues (French: Interuniversity Educational Service Resources for Language Self-Study) | | SPIRAL➣Surface Photometry Interactive Reduction and Analysis Library (Japan) | | SPIRAL➣Society of Pagans Invested in Reviving Ancient Lifestyles (Iowa) |
spiral
Synonyms for spiraladj coiledSynonyms- coiled
- winding
- corkscrew
- circular
- scrolled
- whorled
- helical
- cochlear
- voluted
- cochleate
noun coilSynonyms- coil
- helix
- corkscrew
- whorl
- screw
- gyre
- curlicue
- volute
verb coilSynonymsverb soarSynonyms- soar
- rise
- escalate
- climb
- rocket
- shoot up
phrase spiral downwardsSynonyms- decline
- fall
- drop
- sink
- shrink
- decrease
- deteriorate
- fall off
- dwindle
- wane
- ebb
Synonyms for spiralverb to move or proceed on a repeatedly curving courseSynonyms- coil
- corkscrew
- curl
- entwine
- meander
- snake
- twine
- twist
- weave
- wind
- wreathe
Synonyms for spiralnoun a plane curve traced by a point circling about the center but at increasing distances from the centerRelated Wordsnoun a curve that lies on the surface of a cylinder or cone and cuts the element at a constant angleSynonymsRelated Words- curve
- curved shape
- double helix
noun a continuously accelerating change in the economyRelated Words- economic process
- inflationary spiral
- deflationary spiral
noun ornament consisting of a curve on a plane that winds around a center with an increasing distance from the centerSynonymsRelated Words- decoration
- ornament
- ornamentation
noun a structure consisting of something wound in a continuous series of loopsSynonymsRelated Words- hank
- structure
- construction
noun flying downward in a helical path with a large radiusRelated Wordsverb to wind or move in a spiral courseSynonymsRelated Wordsverb form a spiralRelated Wordsverb move in a spiral or zigzag courseSynonymsRelated Wordsadj in the shape of a coilSynonyms- coiling
- helical
- spiraling
- volute
- voluted
- whorled
- turbinate
Related Words |