vault of heaven; vaulted sky
Poetic or literary term for the sky as a vast dome or arch. Rare in everyday conversation; found in classical or descriptive writing.
Architectural sense: a dome or arched vault. Also rare and literary; modern technical terms like ドーム or アーチ are more common.
Looking up at the night sky, countless stars shone in the vault of heaven.
Beautiful frescoes are painted on the vault of the church.
From Chinese 穹窿 (qiónglóng), meaning 'dome' or 'vault'. The kanji 穹 means 'sky' or 'vault', and 窿 means 'dome' or 'arch'. The exact historical derivation is uncertain; the spelling is conventionally associated with these meanings.