Spiral shell
Spiral Spi"ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster]

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. [1913 Webster]

3. (Geom.) Of or pertaining to a spiral; like a spiral. [1913 Webster]

{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. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Spiral — Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis, and at… …   The Collaborative International Dictionary of English

  • Spiral gear — Spiral Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis,… …   The Collaborative International Dictionary of English

  • Spiral gearing — Spiral Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis,… …   The Collaborative International Dictionary of English

  • Spiral operculum — Spiral Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis,… …   The Collaborative International Dictionary of English

  • Spiral spring — Spiral Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis,… …   The Collaborative International Dictionary of English

  • Spiral wheel — Spiral Spi ral, a. [Cf. F. spiral. See {Spire} a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring. [1913 Webster] 2. Winding round a cylinder or imaginary axis,… …   The Collaborative International Dictionary of English

  • Spiral — Spi ral, n. [Cf. F. spirale. See {Spiral}, a.] 1. (Geom.) A plane curve, not re[ e]ntrant, 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… …   The Collaborative International Dictionary of English

  • Spiral of Archimedes — Spiral Spi ral, n. [Cf. F. spirale. See {Spiral}, a.] 1. (Geom.) A plane curve, not re[ e]ntrant, 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 …   The Collaborative International Dictionary of English

  • spiral — [16] Spiral comes via French spiral from medieval Latin spīrālis ‘coiled’, a derivative of Latin spīra. This in turn went back to Greek speira ‘coil’. English also acquired the noun, as spire [16], which is used for the ‘tip of a spiral shell’.… …   The Hutchinson dictionary of word origins

  • spiral — [16] Spiral comes via French spiral from medieval Latin spīrālis ‘coiled’, a derivative of Latin spīra. This in turn went back to Greek speira ‘coil’. English also acquired the noun, as spire [16], which is used for the ‘tip of a spiral shell’.… …   Word origins

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