An epoch is a distinct period in history marked by important events or characteristics that set it apart from other times. When historians talk about the epoch of the Roman Empire or the epoch of space exploration, they mean a significant stretch of time when particular things were happening that changed how people lived, thought, or understood the world.

The word suggests something more meaningful than just any random period. An epoch represents a time when something fundamental shifted. The invention of the printing press began an epoch of spreading knowledge. The discovery of antibiotics started an epoch of modern medicine. These weren't just interesting moments: they were turning points that helped define entire eras.

Scientists use the word too. Geologists divide Earth's history into epochs, each marked by distinct climate conditions, plant and animal life, or rock formations that make it recognizable and different from the epochs before and after.

You might hear someone describe a moment as epoch-making when it's so significant that it marks the beginning of a new era. Landing on the moon was epoch-making. So was the invention of the internet. These moments didn't just happen: they changed many things that came after.