The word "瘟疫" is formed through a process of semantic compounding, where two characters with closely related meanings are joined to create a single, more potent concept. Each character, 瘟 (wēn) and 疫 (yì), independently carries the ancient idea of a contagious, epidemic disease. By placing them side-by-side, the term doesn't merely add their meanings but intensifies and universalizes them, evolving to represent the overarching concept of a devastating, widespread pandemic. It is a fusion where the whole becomes greater than the sum of its parts, picturing not just an illness but a catastrophic societal scourge.