Crochet thread is specially formulated thread usually made from mercerized cotton for crafting decorative crochet items such as doilies or filet crochet. Crochet thread produces fabric of fine gauge that may be stiffened with starch.
Differences from yarn and sewing thread:
Crochet thread is almost always produced from cotton and has a denser pile and smaller diameter than ordinary yarn. Most crochet threads are thicker in diameter than sewing yarn. Crochet thread can withstand considerable stresses from pulls with sharp hooks.