1. 螺旋(形)
    A spiral is a shape which winds round and round, with each curve above or outside the previous one.

2. (使)盘旋着生长(或移动)
    If something spirals or is spiralled somewhere, it grows or moves in a spiral curve.

    e.g. Vines spiraled upward toward the roof...
           藤蔓盘旋着朝屋顶方向生长。
    e.g. ...a bullet spiralling out of a gun barrel...
           从枪管里飞旋而出的子弹

3. (数量、水平)急遽增长
    If an amount or level spirals, it rises quickly and at an increasing rate.

    e.g. Production costs began to spiral.
           生产成本开始急遽上升。
    e.g. ...a spiralling trend of violence...
           暴力急遽上升的态势

4. (数量、水平)急遽变化
    If an amount or level spirals downwards, it falls quickly and at an increasing rate.

    e.g. House prices will continue to spiral downwards.
           房价将继续暴跌。