n. [ F.; pref. extra- outside + dos (L. dorsum) the back. ] (Arch.) The exterior curve of an arch; esp., the upper curved face of the whole body of voussoirs. See Intrados. [ 1913 Webster ]
n. [ F., fr. L. intra within + F. dos the back, L. dorsum. Cf. Extrados. ] (Arch.) The interior curve of an arch; esp., the inner or lower curved face of the whole body of voussoirs taken together. See Extrados. [ 1913 Webster ]
n.;