From the Tuscan city of Siena, and the earth pigment named for it — reddish brown; from siena. A colour name that entered British and then American use in the 2000s.
Sienna ranks 94th among American girls in 2025, with 2,659 born that year. Its best year was 2025, when 2,659 babies were given the name, ranking 94th. The typical living American called Sienna is about 12 years old today. It is relatively most common in Hawaii, where it accounts for 0.26% of births.
Source: US Social Security Administration, national and state name files, 2025 release, and the Office for National Statistics for England and Wales. Etymology researched and written by our editors. Living-population and median-age figures are our own estimates, described in the methodology.