mountain
岾 centers on a mountain, specifically a mountain pass or ridge. The given meaning 'mountain' is the core idea, with the character likely referring to a mountainous feature.
岾 combines 山 (mountain) with 占, which likely contributes a phonetic element. The exact historical development is uncertain, but the mountain radical clearly indicates a geographical feature.
The left side is a mountain 山, and the right side 占 looks like a person standing on a ridge. Picture a mountain pass where someone stands to survey the peaks.
For やま, imagine a mountain climber named Yama standing on the ridge: Yama -> やま, and he is surrounded by mountains.
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