Search Result for "intrados": 
Wordnet 3.0

NOUN (1)

1. the interior curve of an arch; 



The Collaborative International Dictionary of English v.0.48:

Intrados \In*tra"dos\, 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]


WordNet (r) 3.0 (2006):

intrados
    n 1: the interior curve of an arch