rope, cord
繩 centers on a strong, flexible line made by twisting fibers together: a rope or cord used for tying, binding, or measuring.
繩 combines 糸 (thread) with 黽, which likely contributes the sound and possibly the idea of something long and flexible like a frog or toad, though the exact historical role of 黽 is uncertain.
The left side 糸 shows twisted threads, and the right side 黽 looks like a creature with a long body. Picture twisting many threads into a long, strong rope.
For ジョウ, imagine a rope used by a jō (丈) tall giant to tie things up: jō -> ジョウ, and the rope is as strong as the giant.
inked marking string