calamity
A very serious disaster that harms many people or places.
A calamity is a disaster that causes great damage, suffering, or distress. When an earthquake destroys buildings and leaves families without homes, that's a calamity. When a drought ruins crops and threatens a whole region's food supply, farmers face a calamity.
The word suggests something more severe than everyday problems. Forgetting your homework is frustrating, but not a calamity. A hurricane that floods an entire city is a calamity. A failed test disappoints you, but a serious bus accident is a calamity that affects many families.
Calamities can be natural, like tornadoes, floods, or volcanic eruptions, or they can result from human actions, like a major bridge collapse or an oil spill that poisons a coastline. What makes something a calamity is that it's severe, affects many people seriously, and often requires a major response to fix.
People sometimes use calamity humorously when they're exaggerating. A student might call spilling juice on their shirt a “calamity” even though it's really just inconvenient. But true calamities involve real hardship and require communities to pull together, help each other recover, and rebuild what was lost.