A cotton twill dyed khaki.  Woven from 2-ply combed cotton, the fabric is then mercerized giving it the characteristic shine.  Originally manufactured in Manchester and exported to India, then re-exported to China where it was used to make uniforms for the United States army stationed in the Philippines before World War One until 1925.  The term chino derives from the fact that the fabric was purchased in China although the British army had, for many years, used this hard wearing fabric for uniforms.