brad vs butterfly clip

brad

noun
  • A paper fastener, a fastening device formed of thin, soft metal, such as shim brass, with a round head and a flat, split shank, which is spread after insertion in a hole in a stack of pages, in much the same way as a cotter pin or a split rivet. 

  • A thin, small nail, with a slight projection at the top on one side instead of a head, or occasionally with a small domed head, similar to that of an escutcheon pin. 

verb
  • To upset the end of a rod inserted in a hole so as to prevent it from being pulled out, as when riveting. 

  • To attach using a brad. 

butterfly clip

noun
  • Synonym of split pin (“kind of stationery fastener”) 

  • A hairclip shaped like a butterfly, usually made from brightly colored plastic. 

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