patient zero
Americannoun
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Pathology. the first known carrier of infection in an outbreak.
Public health officials are tracing all contacts of infected patients, trying to work their way back to find patient zero.
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the person or thing that is believed to be the point of origin for any spreading effect, status, or event, especially if negative.
One rowdy new student was patient zero for all kinds of classroom chaos and problem behaviors.
Etymology
Origin of patient zero
First recorded in 1985–90
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The presumed patient zero is a nurse who died in the provincial capital Bunia, but was buried in Mongwalu, also a gold-mining town.
From BBC • May 19, 2026
Isabel Diaz, 53, survived the outbreak with a different stigma -- her father, Victor Diaz, was labeled "patient zero," and attended the birthday party while displaying the early symptoms of hantavirus.
From Barron's • May 11, 2026
I could not identify the patient zero of the cheese-pull phenomenon, but it was around this time that Chili’s became inescapable on TikTok—everyone stretching cheese as far as they could while praising the Triple Dipper.
From Slate • Aug. 11, 2025
McConaughey appears to be patient zero for testing the theory while living in the middle of the United States.
From Los Angeles Times • Mar. 8, 2024
The news reports suggested that one of them could be patient zero.
From New York Times • Jun. 21, 2023
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
