bole vs engobe

bole

noun
  • The shade of reddish brown which resembles this clay. 

  • The trunk or stem of a tree. 

  • Any of several varieties of friable earthy clay, usually coloured red by iron oxide, and composed essentially of hydrous silicates of alumina, or more rarely of magnesia. 

  • An aperture with a shutter in the wall of a house, to admit air or light. 

  • A small closet. 

engobe

noun
  • A clay slip which is colored with metal oxides or stains, used for coating the surface of a pot either before or after bisque firing. 

  • A non-black clay slip coating applied to a ceramic body to give it decorative color or improved texture. 

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