Pronunciation: (stō'mu),[key] —n., —pl.sto•ma•taPronunciation: (stō'mu-tu, stom'u-,[key]stō•-mä'tu), sto•mas. 1. Also,stomate.Bot.any of various small apertures, esp. one of the minute orifices or slits in the epidermis of leaves, stems, etc., through which gases are exchanged.
2. Zool.a mouth or ingestive opening, esp. when in the form of a small or simple aperture.
3. Med.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.