arachnoid vs arachnoid membrane

arachnoid

noun
  • An arachnid. 

  • A round network of fractures in the crust of Venus. 

adj
  • Relating to or resembling spiders. 

  • Relating to or resembling spider webs; covered with or composed of soft loose hairs or fibers. 

  • Relating to the arachnoid mater. 

arachnoid membrane

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