Dun and Grayish brown

Dun noun - A color or pigment varying around a light grey-brown color.

Grayish brown is a synonym for dun. In some cases you can use "Grayish brown" instead a noun "Dun".

Grayish brown noun - A color or pigment varying around a light grey-brown color.

Dun is a synonym for grayish brown. You can use "Dun" instead a noun phrase "Grayish brown".