/ ˈspaɪrəl; NAmE / noun , adjective , verb
■ noun
1.
a shape or design, consisting of a continuous curved line that winds around a central point, with each curve further away from the centre :
The birds circled in a slow spiral above the house.
2.
a continuous harmful increase or decrease in sth, that gradually gets faster and faster :
the destructive spiral of violence in the inner cities
measures to control the inflationary spiral
the upward / downward spiral of sales
■ adjective
moving in a continuous curve that winds around a central point :
A snail's shell is spiral in form.
► spir·al·ly adverb
■ verb ( -ll- , NAmE usually -l- ) [ v , usually + adv. / prep. ]
1.
to move in continuous circles, going upwards or downwards :
The plane spiralled down to the ground.
2.
to increase rapidly :
the spiralling cost of health care
Prices are spiralling out of control.
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PHRASAL VERBS
- spiral down / downward
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WORD ORIGIN
mid 16th cent. (as an adjective): from medieval Latin spiralis , from Latin spira coil, from Greek speira a coil.