Source : Webster's Revised Unabridged Dictionary (1913)

Melanosis \Mel`a*no"sis\, [NL., fr. Gr. ? a growing black, fr.
   me`las, -anos, black.] (Med.)
   The morbid deposition of black matter, often of a malignant
   character, causing pigmented tumors.

Source : WordNet®

melanosis
     n : a condition characterized by abnormal deposits of melanin
         (especially in the skin) [syn: {melanism}]