septenary vs seven

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. 

seven

noun
  • The digit/figure 7 or an occurrence thereof. 

  • A card bearing seven pips. 

num
  • A numerical value equal to 7; the number following six and preceding eight. This many dots: (•••••••). Describing a group or set with seven elements. 

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