heptameter vs septuplet

heptameter

noun
  • a line or verse containing seven metrical feet 

septuplet

noun
  • A group of seven, particularly (music) a tuplet of seven notes. 

  • One of a group of seven, particularly one of seven babies born at the same birth. 

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