crown string, breast harness
纓 centers on ornamental cords or straps used to secure headwear or harnesses: a decorative crown string or a breast harness strap.
纓 combines 糸 (thread) with 嬰, which likely contributes the sound and the idea of something wrapped or tied around the neck or head. The exact historical development is uncertain.
Thread 糸 beside 嬰 (which looks like a woman with ornaments) suggests a decorative cord: imagine a silk string tied around a crown or a horse's chest.
For エイ, picture an elegant 'A'-shaped crown string: the letter 'A' sounds like エイ, and the string forms an 'A' shape when tied.
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