filbert vs hazel

filbert

noun
  • The hazel tree. 

  • The hazelnut. 

  • A paintbrush used in oil and acrylic painting with a long ferrule and a curving, tongue-shaped head. 

hazel

noun
  • The nut of the hazel tree. 

  • The wood of a hazelnut tree. 

  • Freestone. 

  • A tree or shrub of the genus Corylus, bearing edible nuts called hazelnuts or filberts. 

  • A greenish-brown colour, the colour of a ripe hazelnut. 

adj
  • Of a greenish-brown colour. (often used to refer to eye colour) 

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