Derived from Casey, meaning watchful or vigilant.
Caysin is a modern American invention, likely created by blending the traditional Irish surname Casey with the popular '-in' or '-en' suffix. It shares the etymological roots of Casey, which comes from the Gaelic 'cathasaigh', denoting one who is alert or brave.
Fewer than 5 boys were named Caysin in 2025.
US births per 5-year period, 1990–present (SSA data).
