noun
firmament
FUR-muh-munt/ˈfɜːrməmənt/
The sky imagined as an overarching realm.
Bright stars fill the firmament above the quiet mountain town.

Etymology
The 'strong, steadfast' base produced a noun meaning 'a support' or 'a strengthening.' Its heavenly sense reflects a biblical translation that represented the sky as a firm or solid structure.
In context
let birds fly above the earth across the face of the firmament of the heavens
More examples
- A pale moon hangs in the firmament.
- At dawn, the firmament turns from black to gold.
- Her latest novel earns her a place in the literary firmament.
Forms
firmament · firmaments