Cassidy

From an Irish surname which was derived from Ó Caiside meaning "descendant of CAISIDE".

CAISIDE   male   Ancient Irish
Old Irish byname meaning "curly haired", from Irish Gaelic cas.
EQUIVALENTS
ENGLISH: Kassidy
DIMINUTIVES AND SHORT FORMS
ENGLISH: Cass, Cassie
MASCULINE FORMS
ENGLISH: Cass
OTHER FORMS
ANCIENT IRISH: Caiside