bitter orange vs shaddock

bitter orange

noun
  • A citrus tree of the species Citrus limetta. 

  • The fruit of these species. 

  • A citrus tree of the species Citrus ×aurantium, also called Citrus aurantium. 

shaddock

noun
  • Synonym of pomelo, in all its senses including (inexact) grapefruit. 

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