graffiti vs graphite

graffiti

verb
  • To mark a surface with such images. 

noun
  • Drawings or words drawn on a surface in a public place, usually made without authorization. 

  • Informal inscriptions, figure drawings, etc., as opposed to official inscriptions. 

graphite

verb
  • To apply graphite to. 

noun
  • A grey colour, resembling graphite or the marks made with a graphite pencil. 

  • An allotrope of carbon, consisting of planes of carbon atoms arranged in hexagonal arrays with the planes stacked loosely, that is used as a dry lubricant, in "lead" pencils, and as a moderator in some nuclear reactors. 

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