Definitions for unio
Unio, genus Unio(noun)
type genus of the family Unionidae
Any of the genus Unio of freshwater mussels.
Origin: From the genus name.
any one of numerous species of fresh-water mussels belonging to Unio and many allied genera
U.S. National Library of Medicine
A genus of freshwater mussels in the family UNIONIDAE, class BIVALVIA.