Sienna is named after the Tuscan city of Siena, famous for its medieval architecture and the deep orange-red colour of the local clay — the colour we call "burnt sienna," used as an artist's pigment for over five hundred years.
Sienna entered the U.S. top 1000 in 1995 and has been rising. The actress Sienna Miller brought the name into wider awareness in the early 2000s. Today it sits in the U.S. top 100 — a place name turned colour name turned girl name.
Sienna reduces to nine — the number of warmth and quiet generosity.