spiral2 past tense and past participle spiralled, present participle spiralling British English, past tense and past participle spiraled, present participle spiraling American English [intransitive]
1 [always + adverb/preposition]
to move in a continuous curve that gets nearer to or further from its central point as it goes round
spiral to/around etc
The damaged plane spiralled to the ground.
if a situation spirals, it gets worse, more violent etc in a way that cannot be controlled:
Crime has spiraled out of control.
if debt or the cost of something spirals, it increases quickly in a way that cannot be controlled
—spiralling British English ; spiraling American English adjective:
the spiralling cost of legal services