buckram vs harden

buckram

verb
  • To stiffen with or as if with buckram. 

noun
  • A coarse cloth of cotton, linen or hemp, stiffened with size or glue, used in bookbinding to cover and protect the books, in garments to keep them in the form intended, and for wrappers to cover merchandise. 

  • A plant, Allium ursinum, also called ramson, wild garlic, or bear garlic. 

harden

verb
  • To make something hard or harder (tough, resistant to pressure). 

  • To become or make (a person or thing) resistant or less sensitive. 

  • To become or make (a consonant) more fortis; to (cause to) undergo fortition. 

  • To strengthen. 

  • To modify (a website or other system) to make it resistant to malicious attacks. 

  • To unpalatalize or velarize. 

  • To become hard (tough, resistant to pressure). 

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