The word 'khaki' is Persian dust transformed into English fashion. It entered the language through the British Indian Army in the mid-nineteenth century and went on to change the visual identity of warfare itself.
The Persian root is 'خاک' (khāk), meaning 'dust,' 'earth,' or 'soil.' The adjectival form 'خاکی' (khākī), with the Persian suffix '-ī' indicating 'of or pertaining to,' means 'dusty' or 'dust-colored.' The word passed from Persian into Urdu and Hindi, languages deeply influenced by Persian through centuries of Mughal rule in the Indian subcontinent.
The military adoption of khaki is traditionally dated to 1848, during the Second Sikh War on the Northwest Frontier of British India (now in Pakistan). Sir Harry Lumsden, raising the Corps of Guides — an elite regiment of native scouts and infantry — needed practical uniforms for the arid, rocky terrain. The standard British military uniform of the era was white for hot-weather dress and scarlet for formal wear, both disastrously conspicuous in the dust-colored landscape. Lumsden's men dyed their white cotton uniforms with whatever was available:
The practical advantages were immediately apparent. Khaki provided camouflage in the arid terrain, showed dirt less than white, and was psychologically less intimidating to indigenous communities than the scarlet of the regular British army. Other units in India adopted khaki throughout the 1850s and 1860s, and by the Indian Rebellion of 1857 it was in widespread use.
The turning point for global adoption came during the Second Boer War (1899–1902) in South Africa. British troops initially deployed in the traditional scarlet and blue found themselves devastatingly exposed to the long-range marksmanship of Boer commandos armed with modern Mauser rifles. The British Army hastily adopted khaki for all field dress, and the lesson was absorbed by every other major military. By World War I, every major army had adopted some form of earth-toned
After the wars, khaki migrated into civilian clothing. Khaki trousers, khaki shorts, and khaki shirts became standard casual wear, particularly in the United States, where 'khakis' became a generic term for any casual trousers in the yellowish-brown color range. The word now operates as both a color term and a fabric term, sometimes referring to the color regardless of fabric and sometimes to cotton twill cloth regardless of color.
The word has been borrowed into virtually every major language, usually with minimal adaptation: French 'kaki,' Spanish 'caqui,' German 'Khaki,' Japanese 'カーキ' (kāki). It is one of the few Persian words to have achieved truly global reach in modern times.
That the color of modern warfare — and of modern casual trousers — takes its name from the Persian word for 'dust' is a fitting etymology. Soldiers dyed their uniforms to look like the ground they fought on, and they named the color after what it resembled. The word is as literal as language gets: khaki is dust.