The Hebrew word “raqia”, translated as “firmament”, is defined as a beaten out, extended surface, and a solid, vaulted dome.
https://biblehub.com/hebrew/7549.htm
https://www.blueletterbible.org/lexicon/h7549/kjv/wlc/0-1
https://www.kingjamesbibleonline.org/Firmament.php4
In Genesis 1: the name “heaven” is given to the structure of the firmament.
Genesis 1:8
And God called the firmament Heaven. So the evening and the morning were the second day.
The vault of heaven is spread out over earth:
Job 22:14
Clouds are a hiding place for Him, so that He cannot see; And He walks on the vault of heaven.
Amos 9:6
The One who builds His upper chambers in the heavens And has founded His vaulted dome over the earth, He who calls for the waters of the sea And pours them out on the face of the earth, The Lord is His name.
This heavenly ceiling contains waters above it:
Psalms 148:4
Praise Him, highest heavens, And the waters that are above the heavens!
2 Esdras 6:41
Then on the second day you created the spirit of the firmament and commanded that it divide and make a division between the waters so that a certain part might recede upward and another part remain below.