lilac vs perse

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. 

perse

adj
  • Dark greyish blue or purple. 

noun
  • A dark blue-gray colour. 

  • A cloth of this colour. 

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