What is a common noun for imagination?

There isn't really a single, perfect common noun for "imagination." It's a very abstract concept, and the best word to use depends on the context. Here are some possibilities, along with their nuances:

General:

* Creativity: This is a common word for the act of bringing new ideas into existence, which is often associated with imagination.

* Fantasy: This word emphasizes the imaginative and unreal aspects of imagination.

* Vision: This word focuses on the ability to see possibilities and create mental images.

More specific:

* Daydream: This refers to a specific type of imaginative thought that often occurs while daydreaming.

* Idea: This is a very broad term, but it can be used to describe the products of imagination.

* Concept: This emphasizes the abstract and theoretical aspects of imagination.

Ultimately, the best word to use depends on the specific situation and what you want to emphasize.