noun
ZoologyAn orifice in the capsule of phaeodarian actinopods, consisting of a tubular projection or proboscis arising from a radiate operculum.
Origin
Late 19th century; earliest use found in Ernst Haeckel (1834–1919). From astro- (in allusion to the radiate operculum) + -pyle.
Are You Learning English? Here Are Our Top English Tips