pso·ri·a·sis \səˈrīəsə̇s\noun (pluralpsoria·ses \-īəˌsēz\) Etymology: New Latin, from Greek psōriasis, from psōrian to have the itch (from psōra itch, mange) + -iasis; probably akin to Greek psēn to rub — more at sand : a chronic skin disease characterized by circumscribed red patches covered with white scales