The sky, especially when thought of as a solid dome or vault above the Earth; the heavens.
From Latin 'firmamentum,' derived from 'firmus' meaning 'firm' or 'solid.' In ancient times, people imagined the sky as a solid crystalline dome stretching over the flat Earth, supporting the stars and planets.
Medieval Europeans actually believed the firmament was a literal solid sphere of crystal holding the stars—and this poetic image persisted in art and literature even after we learned the sky is just air, showing how beautiful wrong ideas can be.
Complete word intelligence in one call. Free tier — 50 lookups/day.