cliff
磛 centers on a steep, rugged cliff face, emphasizing the sharp, cut-like verticality of a rock wall.
磛 combines 石 (stone) with 斬 (cut, chop), suggesting a cliff as a cut or sheer stone face. The exact historical development is uncertain, but the component relationship is visually clear.
Picture a cliff where the stone (石) has been sharply cut (斬) away, leaving a steep, rugged rock face.
For サン, imagine standing on a cliff under the sun (サン), the sharp cut of the rock face catching the light.