The sky, upper regions; †in early use also, the air, atmosphere. Also plural, the (seven) heavens.

In early cosmography: each of the ‘spheres’ or spherical shells, lying above or outside each other, into which astronomers and cosmographers formerly…

The celestial sphere or firmament, or one of the spheres of the planets, etc. in the ancient astronomy, regarded as revolving like a wheel. Obsolete…

In the Ptolemaic system: A ‘heaven’ or sphere. Obsolete.

One or other of the concentric, transparent, hollow globes imagined by the older astronomers as revolving round the earth and respectively carrying…

? One of the ‘heavens’ or celestial spheres of ancient astronomy (see sphere, n.); also (rarely) one of the heavenly bodies themselves. Obsolete.

Hence, applied sometimes to the other celestial spheres. first firmament n. the Primum mobile.

In the geocentric model of the universe: one of the concentric spheres surrounding and revolving around the earth, in which the moon, sun…

In the medieval version of Aristotle's cosmology: each of the concentric spheres (sphere, n. 2a) supposed to revolve round the earth. first movable n.…

Astronomy. Each of the concentric hollow spheres formerly believed to surround the earth and carry the planets and stars with them in their…

A concave surface or side, a hollow vault; each of the hollow ‘spheres’ of ancient astronomy.

The vault or sphere of the heavens; one of the celestial ‘spheres’ of older astronomy.

A subcelestial region; an earthly sphere. Obsolete. rare.

A celestial sphere (sphere, n. 2a); = orb, n.1 1. Obsolete.