fir vs kelly

fir

noun
  • Any pinaceous conifer of related genera, especially a Douglas fir (Pseudotsuga) or a Scots pine (Pinus sylvestris). 

  • A conifer of the genus Abies. 

  • Wood of such trees. 

kelly

noun
  • A square or hexagonal pipe that is turned in order to rotate the rotary table of a drilling rig. 

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