To revert means to go back to an earlier state, condition, or way of doing things. When a caterpillar becomes a butterfly, it cannot revert to being a caterpillar again. But when your teacher tries a new seating chart and it creates chaos, she might revert to the old arrangement that worked better.

The word often suggests returning to something familiar after trying something new. A family might revert to their regular dinner time after experimenting with eating later. A writer might revert to her original ending after deciding her new one didn't work as well.

In conversations, people sometimes say “let's revert to the original plan” when a backup idea isn't working out. The word carries a sense of undoing a change, like pressing a mental reset button.

You might also hear revert in the phrase “revert to form,” which means someone goes back to their typical behavior. If your usually punctual friend shows up late several days in a row but then arrives early again, you could say she has reverted to form.

One common mistake: people sometimes say “revert back,” but since revert already means to go back, adding “back” is redundant, like saying “return.”