This is whoever will be reading or listening to a piece of work?

That's right! The term for whoever will be reading or listening to a piece of work is audience.

Here are some other terms you might use depending on the context:

* Reader: For written works.

* Listener: For spoken or audio works.

* Viewer: For visual works like films or videos.

* Consumer: For any type of media that is being consumed.

The audience is a crucial element to consider when creating any piece of work, as you need to tailor your message and style to appeal to them.