heather vs lilac

heather

adj
  • Of a purple colour with a tint of pink and blue. 

noun
  • A plant in the family Ericaceae. 

  • Various species of the genus Erica. 

  • Various species of the genus Cassiope. 

  • A purple colour with a tint of pink and blue. 

  • An evergreen plant, Calluna vulgaris, with spiky leaves and small purple, pink, or white flowers. 

  • The use of interwoven yarns of mixed colours to produce flecks. 

lilac

adj
  • Having a pale purple colour. 

noun
  • A flower of the lilac shrub. 

  • A pale purple color, the color of some lilac flowers. 

  • A large shrub of the genus Syringa, especially Syringa vulgaris, bearing white, pale-pink, or purple flowers. 

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