ichthyosis

noun
ich·​thy·​o·​sis | \ ˌik-thē-ˈō-səs How to pronounce ichthyosis (audio) \
plural ichthyoses\ -​ˌsēz How to pronounce ichthyoses (audio) \

Medical Definition of ichthyosis

: any of several diseases usually of hereditary origin characterized by rough, thick, and scaly skin

called also fishskin disease