avalanche

Concise Oxford English Dictionary © 2008 Oxford University Press:
avalanche /ˈavəlɑːnʃ/

▶noun

• 1 a mass of snow, ice, and rocks falling rapidly down a mountainside.

• 2 an occurrence of something in overwhelming quantities.

• 3 Physics a cumulative process in which an ion or electron generates further ions or electrons by collision.

▶verb

• 1 fall in an avalanche.

• 2 Physics undergo a rapid increase in conductivity due to an avalanche process.

– origin C18: from Fr., alt. of Alpine dial. lavanche, influenced by avaler ‘descend’.