high, towering, irregular, rugged
嵳 centers on a mountain that is high and towering, with an irregular or rugged shape. The idea of unevenness or roughness is a natural extension of a steep, jagged peak.
嵳 combines 山 (mountain) with a phonetic component related to 差, suggesting a towering, uneven mountain. The exact historical development of the bottom component is uncertain.
A mountain 山 with a crooked, uneven base 差: picture a towering peak that looks irregular and rugged, like a mountain that can't decide on a smooth shape.
For サ, imagine a towering mountain so high that it seems to reach the sun (サン), but the reading is just サ, so think of the sun peeking over the rugged peak: sun -> サ.
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