ballad : melody music > rarely
Contents
English Expression
  1. n.:  hardly ever,  scarcely ever,  in a rare degree,  It's a wonder,  hard to come by
  2. adj.:  rare
  3. adv.:  rarely,  seldom
French Expression
  1. adj.  précieux, rare, peu fréquent
Thesaurus
infrequence, rarity, seldom