Wordnet 3.0
NOUN (1)
1. 
 congenital malformation of the skull which is long and narrow; 
 frequently accompanied by mental retardation; 
The Collaborative International Dictionary of English v.0.48:
Scaphocephaly \Scaph`o*ceph"a*ly\, n. [Gr. ska`fh a boat +
   kefalh` head.] (Anat.)
   A deformed condition of the skull, in which the vault is
   narrow, elongated, and more or less boat-shaped.
   [1913 Webster]
WordNet (r) 3.0 (2006):
scaphocephaly
    n 1: congenital malformation of the skull which is long and
         narrow; frequently accompanied by mental retardation