WEBa shape made up of curves, each one above or wider than the one before. 螺旋形. A corkscrew is spiral- shaped. 瓶塞钻是螺旋形的。. downward spiral. C2. a situation in which a price, etc. becomes lower, or a situation gets worse and is difficult to control because one bad event causes another. (价格等的)不断下降;(局面 ...