stoma

American  

[stoh-muh] / ˈstoʊ mə /

noun

• stomata,
  plural
• stomas
  plural

1. Botany. Also any of various small apertures, especially one of the minute orifices or slits in the epidermis of leaves, stems, etc., through which gases are exchanged.

2. Zoology. a mouth or ingestive opening, especially when in the form of a small or simple aperture.

3. Medicine/Medical. an artificial opening between two hollow organs or between one hollow organ and the outside of the body, constructed to permit the passage of body fluids or waste products.

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stoma British  

/ ˈstəʊmə /

noun

1. botany an epidermal pore, present in large numbers in plant leaves, that controls the passage of gases into and out of a plant

2. zoology anatomy a mouth or mouthlike part

3. surgery an artificial opening made in a tubular organ, esp the colon or ileum See colostomy ileostomy

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stoma Scientific  

/ stō′mə /

• stomata
  plural

1. Botany One of the tiny openings in the epidermis of a plant, through which gases and water vapor pass. Stomata permit the absorption of carbon dioxide necessary for photosynthesis from the air, as well as the removal of excess oxygen. Stomata occur on all living plant parts that have contact with the air; they are especially abundant on leaves. A single leaf may have many thousands of stomata. Each stoma is generally between 10 to 30 microns in length and is surrounded by a pair of crescent-shaped cells, called guard cells. The guard cells can change shape and close the stoma in order to prevent the loss of water vapor.

2. Botany See Note at transpiration

3. Zoology A mouthlike opening, such as the oral cavity of a nematode.

4. Medicine A temporary or permanent opening in a body surface, especially the abdomen or throat, that is created by a surgical procedure, such as a colostomy or tracheostomy.

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Other Word Forms

Derived Forms

• stomal
  adjective

Inflected Forms

Nouns

• stomas
  plural
• stomata
  plural

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Etymology

Origin of stoma

First recorded in 1675–85; from New Latin, from Greek stóma “mouth”

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Explanation

In humans, a stoma is any opening or hole in the body. In plants, it's an opening that acts as a sort of mouth, allowing gas exchange. Stoma is a Greek word that means "mouth," and your mouth is indeed one kind of stoma, or natural opening in your body. Ears and nostrils are also stomas, as are holes created through surgery. An operation to help a patient breathe might create a stoma in their neck, for example. You can only see tiny plant stomas through a microscope; these small openings allow plants to take in the carbon dioxide they need for photosynthesis.

Example Sentences

See Examples For:

stoma stomas stomata

Paul Scanlon, from Cardiff, has had a stoma for nearly four years after being diagnosed with stage three bowel cancer, external and said he had suffered "degrading" and "humiliating" treatment at UK airports.

From BBC ● Oct. 7, 2026

"I have swallowed more dust than bread," he said in his living room, as he showed the stoma bag he now has to use.

From Barron's ● Aug. 28, 2026

"I always say my stoma bag is just new accessory. It's just another bag and that was where the whole idea came from to like make covers for it and have it as an accessory."

From BBC ● Mar. 24, 2026

Her illness had led to her pulling off her stoma bag that collects bodily waste from the abdomen.

From BBC ● Sep. 22, 2025

B, Air-chamber with the filaments of assimilating cells and stoma in vertical section.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various

She also has two stomas in place for life because much of her bladder and bowel have had to be removed.

From BBC ● Nov. 17, 2024

The model, who made it to the final of the BBC's hit reality series, said her "main goal" after the show was to raise awareness of disabilities and break the taboo around stomas.

From BBC ● Apr. 9, 2024

The Traitors finalist Mollie Pearce says her "main goal" after the show is to raise awareness of disabilities and break the taboo around stomas.

From BBC ● Jan. 30, 2024

She says the reaction from her sto-mates, people who also have stomas, to her being on the show and modelling has been "amazing".

From BBC ● Jan. 30, 2024

She has undergone 16 separate surgeries and has two stomas and catheter.

From BBC ● Jun. 25, 2023

Meanwhile, carbon dioxide enters the leaf through tiny openings called stomata.

From The Wall Street Journal ● Oct. 16, 2026

When leaves release water vapor through their stomata, they start the process of evapotranspiration, which draws water up to the tallest part of a plant, like a beverage being sucked through a straw.

From The Wall Street Journal ● Oct. 16, 2026

When water reaches the leaves, it evaporates through tiny openings known as stomata.

From Science Daily ● Mar. 15, 2026

As carbon dioxide levels in the atmosphere increase, plants may need to open their stomata less frequently, leading to decreased transpiration and preserving more groundwater.

From Los Angeles Times ● Dec. 20, 2024

This difference may be accounted for by the closure of the stomata at night, a phenomenon unknown to Hales.

From Rustic Sounds and Other Studies in Literature and Natural History by Sir Francis Darwin

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