pottage vs stockpot

pottage

noun
  • A thick soup or stew, made by boiling vegetables, grains, and sometimes meat or fish, a staple food throughout Europe in the Middle Ages. 

stockpot

noun
  • A large pot, such as is used for making stock or for cooking large amounts of soup. 

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