mountain in Kansu, where there is a cave into which the sun is said to sink at night
崦 refers to a specific mountain in Kansu (Gansu) province, known in legend for a cave where the sun sinks at night. Its meaning is tied to this geographical and mythological location rather than a general concept.
崦 combines 山 (mountain) with 奄, which likely provides the sound. The character was created to name a specific mountain, so its structure is a straightforward phono-semantic compound.
The left side 山 means mountain, and the right side 奄 looks like a big sun 大 over a sun 日 being covered. Picture the mountain where the sun hides in a cave at dusk.
For エン, imagine the sun ending its day by sinking into the mountain cave: end -> エン, as the day ends at Mount 崦.
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