Merriam-Webster Collegiate Dictionary - umber

 I. noun  Etymology: probably from obsolete English, shade, color, from Middle English ombre, umbre shade, shadow, from Anglo-French, from Latin umbra — more at umbrage  Date: 1568  1. a brown earth that is darker in color than ocher and sienna because of its content of manganese and iron oxides and is highly valued as a permanent pigment either in the raw or burnt state  2.  a. a moderate to dark yellowish brown  b. a moderate brown  II. transitive verb  (~ed; ~ing)  Date: 1610 to darken with or as if with ~  III. adjective  Date: 1802 of, relating to, or having the characteristics of ~; specifically of the color of ~