What is the meaning of Umber?

A brown or reddish pigment used in both oil and water colors, obtained from certain natural clays variously colored by the oxides of iron and manganese. It is commonly heated or burned before being used, and is then called burnt umber; when not heated, it is called raw umber. See Burnt umber, below.

Source: Webster’s Revised Unabridged Dictionary (1913), via OPTED