fettler vs marrow

fettler

noun
  • A friend or mate 

  • A person who maintains railway lines. 

  • Someone who fiddles or tinkers with things. 

  • An ostler; one who looks after the horses in a mine. 

  • Someone whose job is to sand and grind small imperfections from metal and ceramic castings. 

marrow

noun
  • A friend, pal, buddy, mate. 

  • The inner meaning or purpose. 

  • The pith of certain plants. 

  • Bone marrow biopsy. 

  • The essence; the best part. 

  • The substance inside bones which produces blood cells. 

  • A kind of vegetable like a large courgette/zucchini or squash. 

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