Merriam-Webster Collegiate Dictionary - spiral

 I. adjective  Etymology: Medieval Latin ~is, from Latin spira coil — more at spire  Date: 1551  1.  a. winding around a center or pole and gradually receding from or approaching it the ~ curve of a watch spring  b. helical  c. ~-bound a ~ notebook  2. of or relating to the advancement to higher levels through a series of cyclical movements  • ~ly adverb  II. noun  Date: 1656  1.  a. the path of a point in a plane moving around a central point while continuously receding from or approaching it  b. a three-dimensional curve (as a helix) with one or more turns about an axis  2. a single turn or coil in a ~ object  3. something having a ~ form as:  a. ~ galaxy  b.  (1) a ~ flight  (2) a kick or pass in which a football rotates on its long axis while moving through the air  4. a continuously spreading and accelerating increase or decrease wage ~s  III. verb  (-raled or -ralled; -raling or -ralling)  Date: 1834  intransitive verb to go and especially to rise or fall in a ~ course costs ~ed upward  transitive verb  1. to form into a ~  2. to cause to ~