Definitions

1. noun

the sky or heavens considered as a solid vault or structure

“The ancient Greeks believed that the firmament was supported by Atlas.”

2. noun

the upper atmosphere or exosphere

“The firmament of the Earth’s atmosphere is being depleted due to pollution.”

3. noun

the sky or heavens considered as a spiritual realm

“In many cultures, the firmament is seen as a connection between the physical and spiritual worlds.”