septenary vs trio

septenary

noun
  • A group of seven things. 

  • A period of seven years. 

  • The seven notes of the diatonic scale. 

adj
  • Of seventh rank or order. 

  • Consisting of or containing seven. 

  • Lasting seven years; continuing seven years. 

trio

noun
  • A group of three people or things. 

  • A piece of music written for three musicians. 

  • A group of three musicians. 

  • Any cocktail made with a spirit, a liqueur, and a creamy ingredient. 

  • A passage in the middle of a minuet, frequently in a different key. 

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