1890–95; named after J. R. Petri (died 1921), German bacteriologist
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The by-election was a petri dish that Labour had been watching closely, because if Burnham could beat Reform on that stage, it might signal that he could beat Reform in a general election.
From Slate • Jun. 23, 2026
I’m not ashamed to admit that there have been times when those 32-ounce tubs just stare at me day after day, haloed by the refrigerator light, moving further from consumable and closer to petri dish.
From Salon • Apr. 28, 2026
A pilot friend who is crossing the Atlantic from the Canary Islands in a sailboat this month called cruise ships a “floating petri dish.‘
From The Wall Street Journal • Nov. 19, 2025
School and nursery can be like a petri dish with lots of viruses circulating and they may well bring these germs home with them.
From BBC • Oct. 2, 2025
But before she died, a surgeon took samples of her tumor and put them in a petri dish.
From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot
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.
