Plain cotton cloth (6)
I believe the answer is:
calico
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">plain cotton cloth</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for calico that I've seen before include "Type of cotton cloth" , "Given material for dress" , "White cotton fabric" , "Unbleached sixteen down cloth" , "Coarse cloth with a bright print" .)