chain mail vs suit of armour

chain mail

noun
  • A flexible defensive armor, made of a mesh of interlinked metal rings. 

  • A chain letter. 

suit of armour

noun
  • A collection of garments, usually made of metal, worn over the body for protection in battle from weapons. 

How often have the words chain mail and suit of armour occurred in a corpus of books? (source: Google Ngram Viewer )