river in northern Hunan province
澧 is a proper name for a river in northern Hunan province. Its meaning is limited to this specific geographical reference.
澧 combines 氵 (water) with 豊, which likely contributes the sound. It is a phono-semantic compound used as a river name.
Water 氵 beside 豊 suggests a specific river. Picture a map of Hunan with the 澧 River marked by a water symbol next to a sign reading 豊.
For レイ, imagine a ray of sunlight reflecting off the 澧 River: ray -> レイ.
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