briar vs greenbrier

briar

noun
  • Any of many plants with thorny stems growing in dense clusters, such as many in the Rosa, Rubus, and Smilax genera. 

  • The white heath (Erica arborea), a thorny Mediterranean shrub. 

  • Anything sharp or unpleasant to the feelings. 

  • A pipe for smoking, made from the roots of that shrub. 

greenbrier

noun
  • Any of several American prickly woody vines of the genus Smilax; the catbrier. 

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