Indelible means impossible to remove, erase, or forget. When you write with an indelible marker, the ink soaks deep into the surface and can't be washed away. That's why teachers tell you to be careful with permanent markers: one mistake on your desk or clothes, and it's there to stay.

The word often describes things that leave a lasting mark on your memory or character. A trip to see the Grand Canyon might leave an indelible impression on you, meaning you'll remember it vividly for the rest of your life. A teacher who really believed in you might have an indelible influence on the person you become.

Indelible carries a sense of permanence that matters. When a historical event leaves an indelible mark on a nation, it means that event fundamentally changed things in a way that can't be undone. When someone does something truly kind or truly cruel, it can leave an indelible memory that shapes how you see the world. Unlike temporary things that fade or wash away, what's indelible becomes part of the permanent record, whether that's on paper or in your mind.