bilberry vs crackleberry

bilberry

noun
  • The shrub of the above-mentioned plant. 

  • Vaccinium myrtillus, the wild European blueberry of the cowberry family. 

crackleberry

noun
  • The high-bush huckleberry, Gaylussacia baccata, native to eastern North America, or the fruit of this shrub 

  • An imaginary shrub, or the fruit of this shrub 

How often have the words bilberry and crackleberry occurred in a corpus of books? (source: Google Ngram Viewer )