ˈin.trəˌdäs, -ˌdōs, -ˌdō; in.ˈtrā]ˌdäs, -rä], ]_dəs noun
( plural intrados -ˌdōz ; or intradoses -äsə̇z, -ōsə̇z, -əsə̇z\)
Etymology: French, from Latin intra within + French dos back — more at intra- , dossier
1. : the interior curve of an arch ; especially : the inner curved face of the whole body of voussoirs
2. : the inner surface of a vault — compare extrados