quill feather vs rachis

quill feather

noun
  • Any of the larger wing or tail feathers of a bird; sometimes termed a flight feather. 

rachis

noun
  • The central shaft of a feather. 

  • The main shaft of either a compound leaf, head of grain, or fern frond. 

  • An anatomical shaft or axis in a marine invertebrate. 

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