First of all whose khaki? British. Japanese, US?
Khaki, pronounced carkey in English, is a Persian or Pharsee word for dust and that name was given to the dusty colour adopted by the British Army. The dye was originaly Coffie grounds or boiled tea leaves wich was not very permanent. This method of dying was used at the start of WW2 by sailors in the RAN to colour their white No.7s (I think) or shorts and shirt because of the lack of other suitable methods.
TTFN Dai