Small aperture

• A small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass
• Pore, e.g

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Ostiole \Os"ti*ole\, n. [L. ostiolum a little door, dim. of ostium a door: cf. F. ostiole.] (Bot.) The exterior opening of a stomate. See Stomate . Any small orifice.

WordNet Word definitions in WordNet
n. a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass

Wikipedia Word definitions in Wikipedia
An ostiole is a small hole or opening through which algae or fungi release their mature spores . The term is also used in higher plants , for example to denote the opening of the involuted fig inflorescence through which fig wasps enter to pollinate and ...

Wiktionary Word definitions in Wiktionary
n. 1 (context mycology English) A small hole or opening through which certain fungi release their mature spores. 2 (context botany English) A similar hole or opening in plants, such as the opening of the involuted fig inflorescence through which fig wasps ...