What is the X in X-mas?
"dust-colored cloth," 1857, from Urdu khaki, literally "dusty," from khak "dust," from Persian. First introduced in uniforms of British cavalry in India (the Guide Corps, 1846); widely adopted for camouflage purposes in the Boer Wars (1899-1902). As an adjective from 1863. Related: Khakis.
light brown fabric used primarily for military uniforms. It is made with cotton, wool, or combinations of these fibres, as well as with blends of synthetic fibres. It is made in a variety of weaves, such as serge.