heptameter vs octet

heptameter

noun
  • a line or verse containing seven metrical feet 

octet

noun
  • A group or set of eight of something. 

  • A composition for such a group of musicians. 

  • A group of eight musicians performing together. 

  • A byte of eight bits. Abbreviation: o 

  • A group of three bits, representing any of eight possible values. 

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