fir·ma·ment
ˈfərməmənt/
nounliterary
noun: firmament; plural noun: firmaments
the heavens or the sky, especially when regarded as a tangible thing.
synonyms:
the sky, heaven; More
the heavens, the skies;
literarythe empyrean, the welkin
"they lay gazing up at the firmament"
a SPHERE or world viewed as a collection of people.
"one of the great stars in the American golfing firmament"