Definition of fan vault in English:

fan vault

noun

Architecture
  • A type of vault consisting of a set of concave ribs spreading out from a central point like the ribs of an opened umbrella, used especially in the English Perpendicular style.

    • ‘Decoration was now concentrated English-style in roof vaulting, culminating in the fan vaults of Hereford's chapter house (now destroyed) and the cloisters at Gloucester, which were built after 1351.’
    • ‘The chapel is noted for its fine carving and fan vaults. ... These fan vaults once had hanging pendants. Traces of paint are still visible on some of them.’
    • ‘Inside is a fan vault of 1529, an especially fine roof, and monuments to the second and third dukes of York of 1573.’