river in northern china
潞 is a specific proper noun referring to a river in northern China. It has no broader conceptual meaning beyond this geographic name.
潞 combines the water radical 氵 with 路, which likely provides the sound. It was created as a specific character for the name of a river.
The water radical 氵 beside 路 (path) suggests a water path: a river. Picture a specific river in northern China marked on a map with this character.
For ロ, imagine a low, slow-moving river: low -> ロ, and the river's name is 潞.
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