The name of the color khaki coined in British India comes from the Hindustani language (itself a borrowed form of the Persian word khak meaning dust), meaning "dusty, dust covered or earth colored." It has been used by many armies around the world for uniforms, including camouflage. Most notably, khaki was used by the British Army in India beginning in 1848.
The United States Army adopted khaki during the Spanish American War (1898). It has become de rigueur for military uniforms of military forces the world over (e.g., the United States Navy and the United States Marine Corps), as well as the police forces of many South Asian countries and U.S. states and counties.