General:
* Prominence: This is the most direct and common noun for the state of being prominent.
* Importance: This emphasizes the significance or value of something.
* Noticeability: This focuses on how easily something is seen or recognized.
Specific:
* Landmark: Used for a prominent feature in a landscape or a city.
* Figure: Used for a prominent person, often in a particular field.
* Feature: Used for a prominent part of something, like a facial feature.
Examples:
* The mountain's prominence is undeniable.
* She was a figure of great importance in the art world.
* The house's distinctive architectural features made it a local landmark.
Ultimately, the best noun will depend on what you are trying to convey about the prominent thing.