vault (n.)
roof, covering, ceiling
KL V.iii.257[Lear to all] Had I your tongues and eyes I'd use them so / That heaven's vault should crack
TNK I.i.54.1[First Queen to Theseus] we have no roof, / Save this which is ... vault to every thing [i.e. the sky]
SHAKESPEARE'S WORDS © 2018 DAVID CRYSTAL & BEN CRYSTAL