damson vs wax apple

damson

noun
  • The edible fruit of this tree. 

  • A subspecies of plum tree, Prunus domestica subsp. insititia, native to Eurasia. 

adj
  • The color of the fruit of this tree, a very deep purple. 

wax apple

noun
  • the fruit of this plant 

  • a tropical plant, Syzygium samarangense, bearing an edible fruit 

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