An upheaval is a major disruption or dramatic change that turns things upside down. When something causes upheaval, it doesn't just make small adjustments: it shakes up the whole system.

A family might experience upheaval when moving to a new country, where everything from the language to the customs feels unfamiliar and overwhelming. A school might go through upheaval when it merges with another school, suddenly mixing two communities together. Historical upheavals like the Industrial Revolution completely transformed how people lived and worked, moving millions from farms to cities.

The word comes from the image of heaving something up from below, like an earthquake pushing the ground upward or a volcano erupting through the earth's surface. That violent, disruptive feeling carries through to the word's modern meaning.

Upheaval can be exciting or frightening, depending on your perspective. Starting middle school might feel like upheaval to some students: new teachers, new schedules, new social dynamics. While upheaval eventually settles down, the period of change itself can feel chaotic and unsettling. Things that cause upheaval rarely leave situations exactly as they were before.