The Collaborative International Dictionary of English v.0.48:

Dolichocephalic \Dol`i*cho*ce*phal"ic\
   (d[o^]l`[i^]*k[-o]*s[-e]*f[a^]l"[i^]k), Dolichocephalous
\Dol`i*cho*ceph"a*lous\ (d[o^]l`[i^]*k[-o]*s[e^]f"[.a]*l[u^]s),
   a. [Gr. dolicho`s long + kefalh` head.] (Anat.)
   Having the cranium, or skull, long to its breadth;
   long-headed; -- opposed to brachycephalic. --
   Dol`i*cho*ceph"al, a. & n. Dolichocephaly

WordNet (r) 3.0 (2006):

dolichocephalic
    adj 1: having a relatively long head with a cephalic index of
           under 75 [syn: dolichocephalic, dolichocranial,
           dolichocranic] [ant: brachycephalic, brachycranial,
           brachycranic]
    n 1: an adult with a long narrow head