This Greek term refers to the fine, powdery substance that results from dried earth—what we simply call dust. The word appears in two vivid New Testament scenes: Jesus instructing his disciples to shake the dust off their feet as a testimony against unbelieving towns, and merchants weeping over Babylon's destruction by throwing dust on their heads in mourning. The gesture of casting dust on one's head was a traditional sign of grief throughout the ancient Mediterranean world, making the dust itself a symbol of human mortality and sorrow.