firewood vs lumber

firewood

noun
  • Wood intended to be burned, typically for heat. 

lumber

noun
  • Wood sawn into planks or otherwise prepared for sale or use, especially as a building material. 

  • An erect penis. 

  • Useless or cumbrous material. 

  • A baseball bat. 

verb
  • To fill or encumber with lumber. 

  • To move clumsily and heavily; to move slowly. 

  • To heap together in disorder. 

  • To load down with things, to fill, to encumber, to impose an unwanted burden on. 

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