SPIRAL • DICTIONARY ONE.COM • Definition of Spiral

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/spˈaɪrəl/ Listen

noun

Spiral n.

1.

(Geom.) A plane curve, not reentrant, described by a point, called the generatrix, moving along a straight line according to a mathematical law, while the line is revolving about a fixed point called the pole. Cf. Helix.

2.

Anything which has a spiral form, as a spiral shell.

Equiangular spiral,a plane curve which cuts all its generatrices at the same angle. Same as Logarithmic spiral, under Logarithmic.

Spiral of Archimedes, a spiral the law of which is that the generatrix moves uniformly along the revolving line, which also moves uniformly.

adjective

Spiral adj.

1.

Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring.

2.

Winding round a cylinder or imaginary axis, and at the same time rising or advancing forward; winding like the thread of a screw; helical.

3.

(Geom.) Of or pertaining to a spiral; like a spiral.

Spiral gear, or Spiral wheel (Mach.), a gear resembling in general a spur gear, but having its teeth cut at an angle with its axis, or so that they form small portions of screws or spirals.

Spiral gearing, a kind of gearing sometimes used in light machinery, in which spiral gears, instead of bevel gears, are used to transmit motion between shafts that are not parallel.

Spiral operculum, an operculum whih has spiral lines of growth.

Spiral shell, any shell in which the whorls form a spiral or helix.

Spiral spring. See the Note under Spring, n., 4.

See images of 'Spiral'

Etymology of 'Spiral'

Collaborative International Dictionary of English 0.48

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"Spiral" Quotes from Famous Books

... who were carrying me ascended a spiral stairway which led to an immense hall where beds were laid together in three lines, so close that they touched each other. On one of these beds I was placed, in the midst of oaths, cries for pity, and muttered complaints from hundreds of fever-stricken ...

— The Conscript - A Story of the French war of 1813 • Emile Erckmann

... went through the inner lock-door. He saw that the interior of the ship was stripped and bare. But a spiral stairway descended from some upper compartment. It had a handrail of pure, transparent, water-clear plastic. The walls were bare insulation, but that trace of luxury remained. Pop gazed at ...

— Scrimshaw • William Fitzgerald Jenkins

... it almost made one dizzy to watch them. Sometimes they would seem to be standing straight up, facing each other for a few seconds, then they would whirl over and over in regular somersaults, suddenly darting high up in the air, sailing down, at last, in a regular spiral, and landing on the grass right in front ...

— Hollow Tree Nights and Days • Albert Bigelow Paine

... inspecting every cone, cranny and knot hole, chirping his fine, high-keyed notes, sometimes in a querulous tone, and again in the most cheerful and good-natured temper imaginable, now gliding up a tree trunk, now scudding down head foremost, anon circling in a spiral course. ...

— Our Bird Comrades • Leander S. (Leander Sylvester) Keyser

... quarrel of his own accord? I think I see. We find in Algeria a Beetle known as Drilus maroccanus, who, though non-luminous, approaches our Glow-worm in his organization and especially in his habits. He too feeds on land molluscs. His prey is a Cyclostome with a graceful spiral shell, tight-closed with a stony lid which is attached to the animal by a powerful muscle. The lid is a movable door which is quickly shut by the inmate's mere withdrawal into his house and as easily opened when the hermit goes forth. With this ...

— The Glow-Worm and Other Beetles • Jean Henri Fabre

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