What is "siennas"

Usage examples of "siennas".

Russets and ochres and siennas outlined charging boars and fleeing gazelles, woolly mastodons and giant sloths: he imagined that the paintings had to be thousands of years old, but then they turned a corner, and he noticed that, in the same style, there were lorries, house cats, cars, andmarkedly inferior to the other images, as if only glimpsed infrequently, and from a long way awayairplanes.