intrados
/ɪnˈtreɪdɒs
/noun Architecture
The lower or inner curve of an arch. Often contrasted with extrados.The intrados or the inner rim of the arch shows its most distinctive feature - a fringe of lotus-bud carving.
Origin
Late 18th century: from French, from intra- 'on the inside' + dos 'the back' (from Latin dorsum).