VI vs sestet

VI

name
  • VI (“U.S. Virgin Islands”) 

noun
  • verb, intransitive. 

sestet

noun
  • The last six lines of a sonnet, forming two stanzas of three lines each. 

  • A piece of music composed for six voices or six instruments; a sextet or sestuor. 

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