firmament

The vault of the heavens, where the clouds, sun, moon, and stars can be seen; the heavens, the sky.

And thei that be wiſe, ſhal ſhine, as the brightnes of the firmament: & they that turne to righteouſnes, ſhal ſhine as the ſtarres, for euer and euer.

[T]his moſt excellent Canopie the ayre, looke you, this braue orehanging firmament, this maieſticall roofe fretted with golden fire, why it appeareth nothing to me but a foule and peſtilent congregation of vapoures.

The field or sphere of an activity or interest.

the international fashion firmament

Europe dominated foreign policy concerns, followed by the Near East and China, where General George C[atlett] Marshall tried, in vain, to mediate a civil war. Japan glowed dimly in the foreign policy firmament.

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

[B]etweene the ſphere of Saturne and the Firmament, there is ſuch an incredible and vaſt ſpace or diſtance (7000000. ſemidiameters of the earth, as Tycho [Brahe] calculates) void of ſtarres: [...]

But if we yet rise higher, and consider the fixed stars as so many vast oceans of flame, that are each of them attended with a different set of planets, and still discover new firmaments and new lights, that are sunk farther in those unfathomable depths of ether, so as not to be seen by the strongest of our telescopes, we are lost in such a labyrinth of suns and worlds, and confounded with the immensity and magnificence of nature.

The abode of God and the angels; heaven.

Praiſe ye the Lord. Praiſe God in his Sanctuarie: Praiſe him in the firmament of his power.

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

Pins tipt with Diamond Point, and head, / By which the Curls are faſtened, / In radiant Firmament ſet out, / And all over the Hood ſur-tout: [...]

Firmament. Diamonds, or other precious Stones heading the Pins which they stick into the Tour, and Hair, like Stars.