bone marrow vs marrow

bone marrow

noun
  • The fatty vascular tissue that fills the cavities of bones, being the place where new blood cells are produced. 

marrow

noun
  • The substance inside bones which produces blood cells. 

  • The inner meaning or purpose. 

  • The pith of certain plants. 

  • Bone marrow biopsy. 

  • The essence; the best part. 

  • A friend, pal, buddy, mate. 

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

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