Plain-woven cotton fabric
I believe the answer is:
muslin
'plain-woven cotton fabric' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for muslin that I've seen before include "Gauze-like cloth" , "Lightweight cotton fabric" , "Fine soft plain-woven cotton fabric of gauzy appearance" , "dress material" , "Lightweight cotton cloth" .)