burl vs nodule

burl

noun
  • A knot or lump in thread or cloth. 

  • Wood of a mottled veneer, usually cut from such a growth. 

  • A tree growth in which the grain has grown in a deformed manner; a burr knot. 

verb
  • To remove the knots in cloth. 

nodule

noun
  • A rounded mass or irregular shape; a little knot or lump. 

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