petri dish

noun

pe·​tri dish ˈpē-trē- 

variants or less commonly Petri dish

plural petri dishes also Petri dishes

1

: a small shallow usually round dish of thin glass or plastic with a loose cover used especially for growing cells or microorganisms on a supportive medium (such as agar combined with nutrients)

… the protein extracted from human cancer cells could stimulate the growth of blood vessels in experiments with chicken embryos and tumor cells growing in petri dishes.

—Tina Hesman

Unfortunately, most laboratories can diagnose tuberculosis with certainty, or exclude it, only by placing sputum in a petri dish and waiting to see if the bacterium grows …

—The New York Times

… they found that the compound, sulforaphane, fights cancer in petri dishes.

—Doug Levy

2

: something (such as a place or situation) that fosters development

Of course being there for your team tends to contaminate your team. Our radio studio is currently a petri dish of disease.

—Matt Heath

"We view universities as a community's most promising petri dish for innovation," said Abby Taubner …

—Alex Wittenberg

MTV's The Real World, which sends seven attractive young strangers to spend six months turning their luxury housing into a Petri dish of sexual, racial, and interpersonal tension, has been running since 1992.

—Francine Prose

Examples of petri dish in a Sentence

Recent Examples on the Web

Dozens of them are travelling to the International Space Station (ISS) as part of the experiment, enclosed in petri dishes inside a pod that measures 4 by 4 by 12 inches (10 by 10 by 30 centimeters). —Tereza Pultarova, Space.com, 9 Apr. 2026

In February 2025, Kiers’s team of ecologists joined forces with Tom Shimizu’s biophysicists from the AMOLF Institute in Amsterdam to robotically track how nutrients flow within hyphae growing in petri dishes. —Quanta Magazine, 6 Apr. 2026

These white threads are cloaked in sheaths of chitin — the same sugar polymer that forms the tough exoskeletons of beetles, crabs, and lobsters — and can be easily grown in flasks and Petri dishes. —Big Think, 31 Mar. 2026

In addition to Flea and Kiedis, the documentary boasts interviews of varying levels of substance with Jack Irons and Alain Johannes, giving an intriguing breakdown of the Petri dish in which the Chili Peppers and What Is This formed, broke up and achieved success. —Daniel Fienberg, HollywoodReporter, 15 Mar. 2026

Word History

Etymology

Julius R. Petri †1921 German bacteriologist

First Known Use

1892, in the meaning defined at sense 1

Rhymes for petri dish

• cuttlefish
• jellyfish
• sablefish
• bluefish
• catfish
• codfish
• crawfish
• dogfish
• finfish
• flatfish
• goldfish
• groundfish

Kids Definition

Petri dish

noun

Pe·​tri dish

ˌpē-trē-

: a small shallow dish of thin glass or plastic with a loose cover used especially for cultures of bacteria

Medical Definition

petri dish

noun

pe·​tri dish

variants also Petri dish

ˈpē-trē- 

: a small shallow usually round dish of thin glass or plastic with a loose cover used especially for growing cells on a supportive medium (such as agar combined with nutrients)