watery expanse
涬 centers on a vast, open body of water: a watery expanse. The meaning is narrow and concrete, describing a large stretch of water.
涬 combines the water radical 氵 with 幸, which likely contributes a phonetic element. The exact historical development is uncertain, but the character is used to represent a watery expanse.
The water radical 氵 beside 幸 suggests a fortunate, vast stretch of water. Imagine a lucky sailor finding an endless, calm watery expanse.
For ケイ, picture a kayak gliding across the watery expanse: kayak -> ケイ, and the water stretches out in all directions.
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