from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A small opening or pore, as of a fruiting body.

from The Century Dictionary.

  • noun A small opening or entrance; a little ostium.
  • noun In zoology: One of the small inhalant pores or orifices of sponges.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The exterior opening of a stomate. See stomate.
  • noun Any small orifice.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun mycology A small hole or opening through which certain fungi release their mature spores.
  • noun botany A similar hole or opening in plants, such as the opening of the involuted fig inflorescence through which fig wasps enter to pollinate and breed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass


from The American Heritage® Dictionary of the English Language, 4th Edition

[Latin ōstiolum, diminutive of ōstium, opening; see ostium.]


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