Auburn is a beautiful reddish-brown color that's frequently described as having a warm, earthy feel. Some synonyms for auburn include chestnut, russet, mahogany, and copper. Chestnut is a deep, rich brown color that resembles the nut of the same name, while russet is a darker, reddish-brown color that's often described as "autumnal." Mahogany is a deep, dark brown with a reddish tinge, while copper is a reddish-brown, metallic color that's inspired by the metal of the same name. All of these colors can be used to describe hair, but they're also frequently used to describe natural materials, like wood or leather.