Meaning

• (usually uncountable) The vault of the heavens, where the clouds, sun, moon, and stars can be seen; the heavens, the sky.

• The field or sphere of an activity or interest.

  "the international fashion firmament"

• In the geocentric Ptolemaic system, the eighth celestial sphere which carried the fixed stars; (by extension) any celestial sphere.

• (obsolete except biblical) The abode of God and the angels; heaven.

• A piece of jewellery worn in a headdress with numerous gems resembling stars in the sky.

• A basis or foundation; a thing which lends strength or support.

• The act or process of making firm or strengthening.