Cassidy

Part of speech: noun

Definitions

1. An Irish surname, also used as a given name, derived from a Gaelic family name meaning clever or curly-haired
2. A personal name of Irish origin that is also carried as a family surname by many people of Irish descent
3. Used as a first name or family name, originating from an Irish Gaelic personal name in the Ó Caside tradition

Etymology: The name Cassidy is an anglicised form of the Irish surname Ó Caiside, meaning "descendant of Caiside." The personal name Caiside is itself built on "cas," an Irish word for "curly-haired," so the family name began as a nickname for someone with a mop of curls before it became a hereditary surname passed down through generations. Irish surnames beginning with "Ó" (meaning "descendant of" or "grandson of") were formed this way across the country, and many were later simplified or respelled in English-speaking countries. Cassidy is a good example: the original Gaelic form Ó Caiside lost its "Ó" and took on an English spelling, so the curly-haired ancestor's name survives in a form that most people who carry it have never seen written in Irish.