snap fastener vs trappings

snap fastener

noun
  • a pair of male/female interlocking disks used to fasten a piece of clothing in place of buttons 

trappings

noun
  • Clothing or equipment; that which gives the appearance of something. 

  • Ornamental coverings or harnesses for a horse; caparisons. 

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