plural noun Uni·on·i·dae

Definition of Unionidae

  1. :  a very large family of freshwater mussels (suborder Submytilacea) having a pearly often roughly sculptured shell with a thick epidermis and larvae that pass through a glochidium stage and being represented in nearly all parts of the world but chiefly in North America where the nacreous shells of many of them are used for button making

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Origin and Etymology of unionidae

New Latin, from Union-, Unio, type genus + -idae

Seen and Heard

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a rounded knoll or a ridge of ice

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