Below you can find the Often mercerized for strength & appearance this is the natural fiber most used to make thread Jeopardy Words Answer. The answer to Often mercerized for strength & appearance this is the natural fiber most used to make thread has 6 letters. This clue belongs to the Sewing category and is part of Jeopardy Word Level 1859. If you scroll near the bottom you will find other clues and answers part of level 1859