tightly twisted thread
A thread with a strong, tight twist, often used in sewing or crafts where durability or a textured effect is desired.
Tightly twisted thread is often used for sewing leather goods because it makes the seams strong.
Compound of 蛇腹 (jabara, 'bellows; zigzag') and 糸 (ito, 'thread'), referring to the thread's twisted, bellows-like structure.