Definition of "irruption" [ir•rup•tion]

• The action of irrupting or breaking into; a violent entry or invasion; an inbreaking; an intrusion. (noun)
• An abrupt increase of numbers of a particular animal. (noun)

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• "The white, two-foot-tall birds, which live in the Arctic the rest of the year, are known to fly south in large numbers every few winters in what is known as an irruption."
• "And should the "political" be defined as the irruption of something that is denied recognition?"
• "Charlotte is poorly with cold and toothache attended with a general kind of irruption on the skin."