Source : Webster's Revised Unabridged Dictionary (1913)

Hydrocephalus \Hy`dro*ceph"a*lus\, n. [NL., fr. Gr. ?
   hydrocephalus; "y`dwr water + ? head.] (Med.)
   An accumulation of liquid within the cavity of the cranium,
   especially within the ventricles of the brain; dropsy of the
   brain. It is due usually to tubercular meningitis. When it
   occurs in infancy, it often enlarges the head enormously.

Source : WordNet®

hydrocephalus
     n : an abnormal condition in which cerebrospinal fluid collects
         in the ventricles of the brain; in infants it can cause
         abnormally rapid growth of the head and bulging
         fontanelles and a small face; in adults the symptoms are
         primarily neurological [syn: {hydrocephaly}]