excise vs shale

excise

verb
  • To cut out; to remove. 

  • To impose an excise tax on something. 

noun
  • A tax charged on goods produced within the country (as opposed to customs duties, charged on goods from outside the country). 

shale

verb
  • To take off the shell or coat of. 

noun
  • A shell or husk; a cod or pod. 

  • A fine-grained sedimentary rock of a thin, laminated, and often friable, structure. 

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