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• petri dish
  petri dish

  noun

  a shallow, circular, glass or plastic dish with a loose-fitting cover over the top and sides, used for culturing bacteria and other microorganisms.
• Petri dish
  Petri dish

  noun

  a shallow circular flat-bottomed dish, often with a fitting cover, used in laboratories, esp for producing cultures of microorganisms

petri dish

American  

[pee-tree] / ˈpi tri /

noun

1. a shallow, circular, glass or plastic dish with a loose-fitting cover over the top and sides, used for culturing bacteria and other microorganisms.

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Petri dish British  

/ ˈpɛtrɪ /

noun

1. a shallow circular flat-bottomed dish, often with a fitting cover, used in laboratories, esp for producing cultures of microorganisms

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petri dish Scientific  

/ pē′trē /

1. A shallow, circular dish with a loose cover, usually made of transparent glass or plastic and used to grow cultures of microorganisms. The petri dish is named after German bacteriologist Julius Richard Petri (1852–1921).

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Etymology

Origin of petri dish

1890–95; named after J. R. Petri (died 1921), German bacteriologist

Example Sentences

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

"To hear that there's going to be the potential of some of these very preventable diseases becoming a petri dish here in our location is troublesome," she said.

From BBC • Sep. 14, 2025

If by “effort” she means writing a check that could send a small village to college, then she definitely put in quite a bit of effort just so I could be a human petri dish.

From "Five Feet Apart" by Rachael Lippincott