Cassidy
The story
Cassidy is the Irish surname Ó Caiside worn as a given name, built on cas, twisted, curly, so the oldest meaning is simply curly-haired. America heard it as music first: it arrived in numbers in the 1970s, the Partridge Family years, when David Cassidy was the poster on every wall, about 870 that decade from nearly none before. The climb never paused: 4,500 in the 1980s, 21,600 in the 1990s, cresting at 21,700 in the 2000s, a two-decade run at the top before the drift to 11,800 in the 2010s and 4,210 so far. It goes overwhelmingly to girls, about 60,800 to 3,700. Cassie comes built in, the same hand-me-down Cassandra offers, and Casey, at about 194,800, keeps the family's C-sound in circulation. Curly-haired in Gaelic, straight-A American since the seventies: Cassidy wears both.
Popularity, 1890–2024
Shape drawn from US Social Security baby-name records. Cassidy peaked in the 2000s.
When you meet Cassidy
Most people given the name Cassidy in the United States are teenagers or young adults today.
Estimated from US Social Security birth registrations and typical lifespans; a rough guide, not a rule.
The Cassidy deep dive
Whether you’re naming a baby or exploring your own name’s history, this is a personal letter, not a list: where Cassidy truly comes from, how it traveled, and what a century of records reveals. If you have grown a tree on nametree, it also considers how Cassidy fits with your family’s names and surname.
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