The word 死亡 is formed through the pairing of two characters that each independently convey the idea of cessation or ending. The first character, 死, directly depicts the concrete, physical act of dying or death itself. It is combined with 亡, which carries a more abstract sense of perishing, vanishing, or being lost. Together, they create a compound that merges the immediate act with the resulting permanent state of non-existence, thereby reinforcing and encompassing the complete, final concept of mortality.