Khaki went from India to the Kaffir War in South Africa in 1851, and then after the Sudan Wars and Afghan Campaign of 1878 it was adopted in 1884 as the official uniform. The same year Khaki-color dye was patented. It soon was adopted by other armies including America for the Spanish-American War in 1898. The British Khakis found their way into China where they were duplicated and sold to American soldiers in the Philippines for uniforms. Chinos don't have to be twill, but are often a firm weave of cotton.
Chinos can be Khaki color.
The military style had no pleats and was tapered at the leg bottom to conserve fabric. When soldiers returned to civilian life from WWII they continued to wear their military chinos especially to college. Reportedly, Bill's Khakis is one of the best pants on the market. And L. L. Bean stocks jeans to chinos. They were pants invented by Elizabeth Smith Miller and consisted of a short skirt with baggy trousers gathered at the ankles.