Cassidy
Meanings & Origins
"curly-haired"
"descendant of Caiside"
Popularity
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“A spirited Irish name with Wild West swagger”
Origin & Etymology
Cassidy derives from the Irish surname Ó Caiside, thought to descend from a clan chief named Caiside — the name possibly related to 'cas' meaning curly or twisted. The name came to North America with Irish immigrants and found especially fertile ground in the American West, where the outlaw Butch Cassidy made it legendary. Today it is used almost exclusively for girls, completing one of the more dramatic surname-to-girls'-name transformations in American naming history.
Popularity Story
Cassidy peaked as a girls' name in the early 2000s, riding waves of Western-chic naming and the popularity of friendly names ending in '-y.' The Grateful Dead's song 'Cassidy' (1974) gave it early countercultural credibility, and the name remained in the US Top 100 from 1994 to 2014.
Cultural Significance
The name carries distinct Western American energy, inseparable from Butch Cassidy's outlaw legend. For Irish-Americans, it also reflects ancestral heritage from County Fermanagh, where the Ó Caiside clan originated. This Celtic-meets-frontier combination makes Cassidy uniquely resonant in American culture.
Fun Facts
- Butch Cassidy (born Robert Leroy Parker) took the surname 'Cassidy' from his cattle-rustling mentor Mike Cassidy
- The Grateful Dead wrote 'Cassidy' in 1974, naming it for a baby born to a friend — it became one of their most beloved songs
- Cassidy was in the US Top 100 girls' names continuously from 1994 to 2014