Rex

Rex is an unusual choice for a female name, as it is traditionally masculine in origin. Derived from Latin, Rex means "king" and carries a sense of authority and regality. While predominantly used for boys, some parents may choose Rex for a girl seeking a strong, commanding name with gender-neutral appeal. The name has ancient royal associations, being the Latin title for a king or monarch. As a female name, Rex remains extremely rare, offering a bold, distinctive option that breaks conventional naming patterns. It could be considered part of the trend toward traditionally masculine names being adopted for girls, similar to names like James and Ryan that have crossed gender lines in recent years.

Pronounced REKS.

As of October 2026, Rex ranked #10051 in US births in 1984 SSA, peaked at #3610 in 1925.