The Collaborative International Dictionary of English v.0.48:

Elephantiasis \El`e*phan*ti"a*sis\, n. [L., fr. Gr. ?, from
   'ele`fas, 'ele`fantos, an elephant.] (Med.)
   A disease of the skin, in which it become enormously
   thickened, and is rough, hard, and fissured, like an
   elephant's hide.
   [1913 Webster]

WordNet (r) 3.0 (2006):

elephantiasis
    n 1: hypertrophy of certain body parts (usually legs and
         scrotum); the end state of the disease filariasis