Encephalos

from The Collaborative International Dictionary of English v.0.48

Encephalos \En*ceph"a*los\, n. [NL., fr. Gr. 'egke`falos; 'en in
   + kefalh` head.] (Anat.)
   The encephalon.
   [1913 Webster]

         In man the encephalos reaches its full size about seven
         years of age.                            --Sir W.
                                                  Hamilton.
   [1913 Webster]