Pronunciation: (spī'rul),[key] —n., adj., v.,-raled, -ral•ing or (esp. Brit.)-ralled, -ral•ling.
—n. 1. Geom.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. Aeron.a maneuver in which an airplane descends in a helix of small pitch and large radius, with the angle of attack within that of the normal flight range.
6. Football.a type of kick or pass in which the ball turns on its longer axis as it flies through the air.
7. Econ.a continuous increase in costs, wages, prices, etc. (inflationary spiral), or a decrease in costs, wages, prices, etc. (deflationary spiral).
—adj. 1. running continuously around a fixed point or center while constantly receding from or approaching it; coiling in a single plane: a spiral curve. 2. coiling around a fixed line or axis in a constantly changing series of planes; helical.
3. of or of the nature of a spire or coil.
4. bound with a spiral binding; spiral-bound: a spiral notebook.
—v.i. 1. to take a spiral form or course.
2. to advance or increase steadily; rise: Costs have been spiraling all year. 3. Aeron.to fly an airplane through a spiral course.