Source : Webster's Revised Unabridged Dictionary (1913)

Khaki \Kha"ki\ (k[aum]"k[-e]), a. [Hind. kh[=a]k[=i], lit.,
   dusty, dust-colored, fr. Per. kh[=a]k dust.]
   Of a dull brownish yellow, or drab color; -- applied to
   cloth, originally to a stout brownish cotton cloth, used in
   making uniforms in the Anglo-Indian army.

   Note: In the United States service the summer uniform of
         cotton is officially designated khaki; the winter
         uniform of wool, olive drab.

Khaki \Kha"ki\, n.
   Any kind of khaki cloth; hence, a uniform of khaki or,
   rarely, a soldier clad in khaki. In the United States and
   British armies khaki or cloth of a very similar color is
   almost exclusively used for service in the field.

Source : WordNet®

khaki
     adj : of a yellowish brown color
     n : a sturdy twilled cloth of a yellowish brown color used
         especially for military uniforms