madder vs redbird

madder

noun
  • A dye made from the plant. 

  • A deep reddish purple colour, like that of the dye. 

  • The root of the plant, used as a medicine or a dye. 

  • A herbaceous plant, Rubia tinctorum, native to Asia, cultivated for a red-purple dye (alizarin) obtained from the root. 

adj
  • Of a deep reddish purple colour, like that of the dye. 

redbird

noun
  • A capsule of secobarbital. 

  • Any of various red cars formerly used in the New York City subway system; or a train of such cars. 

  • Any of several unrelated American songbirds having red plumage, especially the tanager or cardinal. 

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