thicket vs woad

thicket

noun
  • A dense, but generally small, growth of shrubs, bushes or small trees; a copse. 

  • A dense aggregation of other things, concrete or abstract. 

  • The collection of many small linked files created when a document is saved in HTML format by some word processors and web site creation software. 

woad

noun
  • The plant Isatis tinctoria. 

  • The blue dye made from the leaves of the plant. 

verb
  • To plant or cultivate woad. 

  • To dye with woad. 

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