Of Italian origin.
From the name Sienna, spelled according to the name of the Italian city Siena.
The city of Siena is proclaimed by Unesco as a World Heritage site.
Sienna is the word used to define the color deriving from clay earth pigment “sienna”, which has this orange-red look because it contains iron and manganese oxide.
It’s origin is Italian, from “terra di Siena”, meaning ” Siena earth”.
Alternative form of the name is Sienna.