Firmament (noun)

1. The arch or vault of the heavens, in which the sun, moon, and stars appear to be located.
2. The sky; the heavens.

Origin:

Middle english: from old french firmament, from latin firmamentum, from firmare "to make firm".

Examples:

1. The stars shone brightly in the firmament.
2. The firmament was a beautiful shade of blue during the sunset.
3. According to ancient belief, the firmament was a solid dome that separated the earth from the heavens.
4. The firmament is the home of the gods in many ancient myths.
5. The firmament is full of celestial bodies that we can observe with telescopes.