Left earth radical, a pictograph of a clod or mound of soil rising from the ground. The indexing element. Puts
墩 in the earthwork family with
块 (block),
堆 (pile),
堡 (fort),
坝 (dam),
坟 (mound, tomb). The radical states the substance: a
墩 is a solid block of earth, stone, or masonry, a pier, plinth, or pillar-base anchored in the ground.