bridge, bank
圯 centers on a raised earthen structure: a bridge or an embankment. Both meanings share the idea of earth built up to cross or contain water.
圯 combines 土 (earth) with 巳, which likely contributes the sound. The exact historical development is uncertain, but the earth component fits the meaning of an earthen bridge or bank.
The left side is earth 土, and the right side 巳 looks like a coiled snake. Picture a snake-shaped earthen bridge arching over a river.
For イ, imagine an earthen bridge in Italy: Italy -> イ, and the bridge spans a canal.
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