The word 灾难 is formed by combining two characters, each representing a related aspect of misfortune. The first character, 灾 (zāi), conceptually means a disaster or calamity, often from natural or external forces like fire or flood. The second, 难 (nàn), represents hardship, tribulation, or suffering endured by people. They are placed together not by grammar but by fused meaning, creating a compound concept where an external catastrophe (灾) meets and causes profound human suffering and difficulty (难), thus fully capturing the idea of a devastating "catastrophe" or "disaster".