hy·dro·ceph·a·lus (hī'drō-sěf'ə-ləs) n. A usually congenital condition in which an abnormal accumulation of fluid in the cerebral ventricles causes enlargement of the skull and compression of the brain, destroying much of the neural tissue.
[New Latin, from Greek hudrokephalon : hudro-, hydro- + kephalē, head; see ghebh-el- in Indo-European roots.] hy'dro·ce·phal'ic (-sə-fāl'ĭk), hy'dro·ceph'a·loid' (-loid'), hy'dro·ceph'a·lous (-ləs) adj.