beetroot vs sugar beet

beetroot

noun
  • The edible part of the root of a beet plant, raw or prepared. 

  • A normally deep-red-coloured root vegetable usually cooked or pickled before eating; Synonym of beet. 

verb
  • To turn a bright red or purple colour. 

sugar beet

noun
  • A type of beet whose root contains a high concentration of sucrose. 

  • darling; sweetheart 

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