noun, plural in·tra·dos [in-truh-dohz, in-trey-dohz] /ˈɪn trəˌdoʊz, ɪnˈtreɪ doʊz/, in·tra·dos·es. Architecture.
Examples from the Web for intrados
The lower surface or soffit of the arch is the intrados, E, and the upper surface the extrados, F.
Intrados: The under or concave face of the solid structure of an arch.How to judge architecture|Russell Sturgis
It was determined to attempt to stop these leaks by the application of a water-proof cement coating on the intrados of the arch.Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910|James H. Brace and Francis Mason
The under or concave side of the voussoirs is called the intrados, and the upper or convex side the extrados of the arch.
In S. Sophia the vault springs from the intrados of the transverse arches, that is, from the lower edge.Byzantine Churches in Constantinople|Alexander Van Millingen