Also stomate. Botany. 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.
Zoology. a mouth or ingestive opening, especially when in the form of a small or simple aperture.
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.
- stomal, adjective
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British Dictionary definitions for stoma
botany an epidermal pore, present in large numbers in plant leaves, that controls the passage of gases into and out of a plant
zoology anatomy a mouth or mouthlike part
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for stoma
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. See Note at transpiration.
Zoology A mouthlike opening, such as the oral cavity of a nematode.
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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.