Dictionary
ex•tra•dos
Pronunciation: (ek'stru-dos", -dōs", ek-strā'dos, -dōs), [key]—
n.,
—pl. -dosPronunciation: (-dōz", -dōz), [key] -dos•es.
Archit.
the exterior curve or surface of an arch or vault. Also called
back. Cf.
intrados. See diag. under
arch. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.