copper vs copperhead

copper

noun
  • Any of various lycaenid butterflies with copper-coloured upperwings, especially those of the genera Lycaena and Paralucia. 

  • The reddish-brown colour/color of copper. 

  • A police officer. 

  • A reddish-brown, malleable, ductile metallic element with high electrical and thermal conductivity, symbol Cu, and atomic number 29. 

adj
  • Made of copper. 

  • Having the reddish-brown colour/color of copper. 

verb
  • To sheathe or coat with copper. 

copperhead

noun
  • Coelognathus radiatus (syn. Elaphe radiata), the copperhead rat snake, a non-venomous colubrid species found in southern Asia. 

  • Someone with ginger hair. 

  • Agkistrodon contortrix, a venomous pit viper species found in parts of North America. 

  • Deinagkistrodon acutus, the Chinese copperhead, a venomous pit viper species found in Southeast Asia 

  • Austrelaps spp. (Australian copperheads), a genus of venomous elapids found in southern Australia and Tasmania. 

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