ˈmīsə̇s noun
Etymology: New Latin, from Greek mysis action of closing (used of the lips or eyes), from myein to close (used of the lips or eyes), close the eyes + -sis — more at mystery
1. capitalized : the type genus of the family Mysidae
2. or mysis stage -es : a larva of higher crustaceans (as macrurans and peneids) having all the thoracic appendages biramous