This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
緭 combines 糸 (thread) with 胃, which likely contributes the sound. The exact historical development is uncertain.
The left side is thread 糸, and the right side is stomach 胃. Picture a thread tied around a stomach, but the meaning is unclear.
For イ, imagine a single thread (糸) tied around the stomach (胃) of an eagle (イーグル): eagle -> イ.