The term 'A BLACK KEY' can be solved in four different ways using crossword solutions. The first solution is EBONY, which is a dark black wood that is often used to make furniture and musical instruments. The second solution is EBON, which is a black or dark gray color. The third solution is EFLAT, which is a musical note that is one semitone lower than the note E. The fourth solution is GFLAT, which is a musical note that is one semitone lower than the note G. All of these solutions refer to the term 'A BLACK KEY' in some way.