black selenium: Meaning and Definition of

black' sele'nium

Pronunciation: [key]
— Chem. Chem.
  1. an allotropic form of selenium occurring as a black, amorphous, water-insoluble, light-sensitive powder: used chiefly in photoelectric cells.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.