rope
縻 centers on a rope used to bind or tie, often with the nuance of a tether or leash that restrains.
縻 combines 糸 (thread) with 麻 (hemp), suggesting a rope made from hemp fibers. The character likely developed as a specific term for a tethering rope.
Outside is 麻 (hemp), inside is 糸 (thread). Picture twisting hemp threads together to make a strong rope for tying things up.
For ビ, imagine a bee tied to a rope: bee -> ビ, and the bee buzzes against its hemp tether.
tying down; fastening; binding