tower

塔 is composed of 土 (soil) and 荅 (pod, respond). 荅 is formed from the radical 艸 (grass) and 合 (fit, together), originally referring to leguminous plants with pods, but here it draws on the meaning of 合, which implies coverage. Covering or piling soil can create elevated structures, and soil was an important building material in ancient times, so 塔 refers to a tall, towering building, such as a pagoda or tower.