khaki n.

"dust-colored cloth," 1857, from Urdu khaki, literally "dusty," from khak "dust," a word from Persian. Used principally at first for uniforms of British cavalry in India, introduced in the Guide Corps, 1846; widely adopted for camouflage purposes in the Boer Wars (1899-1902). It once had overtones of militarism. As an adjective from 1863. Related: Khakis.