The "habitable zone" refers to the region around a star where conditions may be suitable for liquid water to exist on a planet's surface. This zone is often called the "Goldilocks zone" because it is not too hot and not too cold, allowing for the possibility of life as we know it. The distance from the star determines the temperature, and different stars have different habitable zones. Planets within the habitable zone, such as those in the Solar System like Earth, have the potential to support life. However, other factors, such as a planet's atmosphere and geological activity, also play crucial roles in determining its habitability.