bitter orange vs satsuma

bitter orange

noun

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

  • A citrus tree of the species Citrus limetta. 

  • The fruit of these species. 

satsuma

noun

  • A seedless and easy-peeling cultivar of mandarin orange of Japanese origin; Citrus unshiu. 

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