Definition of "metastasize"

On other screens are closeups of skin pores, before and after, details of regimes for everything, your hands, your neck, your thighs. Your elbows, especially your elbows: aging begins at the elbows and metastasizes.

1989, Margaret Atwood, Cat's Eye

‘Your lump could be a secondary cancer metastasized from the bowel. I had a patient like that not long ago.’

2001, David Lodge, Thinks...

“I remember the first time he woke up throwing up, and my first thought wasn't, ‘Oh he has the stomach flu,'” she said. “It was, ‘Oh, it's gone to his brain, and it's metastasized his brain, and he's throwing up because of that.'”

2013 May 11, Jaclyn Cosgrove, “Fostering hope: Doctor learns about being a mother to child with cancer”, in The Oklahoman‎

If enough Americans expose themselves to the virus and become immune, the theory goes, the country would have a mobilized cadre of immune citizens. […] The article was widely discredited by public health experts and economists, as both logically dubious and ethically specious, but such thinking has already metastasized.

2020 April 12, Kathryn Olivarius, “The Dangerous History of Immunoprivilege”, in The New York Times‎

In a broader sense, criticism as a form is in trouble. And celebrities like Grande, like Che, like Munn, who swat at it to the delight of their fans, concerningly seem to metastasize the problem.

2019 April 26, Richard Lawson, “Why Critics Worry About Criticism”, in Vanity Fair‎