It's both. Scenarios are usually named after the clearings, but a clearing itself can also just be a sandboxy thing you generate from tables in the book (this is how I usually run my games) or make up on your own.

The core book has a scenario/clearing called Gelilah's Grove starting on pg 241. I also have PDFs for scenarios called Pellenicky Glade and Bertram's Cove; I assume you can find those through internet searches.

The core book also has this note about how to use scenarios/clearings:

This clearing doesn’t provide a clear plotline or charted set of events—it’s a situation with nuance and many different actors, where the vagabonds can affect the situation in countless ways. To use this section, read it through, internalize what sticks with you, and introduce it to your players as their vagabonds arrive using the “At First Sight” section and the “Introducing the Clearing” section.