extrados

/ˈɛkstrəˌdɑs/
noun
  1. The outer curve or surface of an arch (as opposed to the inner curve, called the intrados).
    • The extrados of the dome was decorated with intricate carvings.
    • Cracks appeared along the extrados of the bridge arch.
    • The architect measured the extrados of the stone arch.
Antonyms
What does "extrados" mean? | whatsthatwordmean | whatsthatwordmean