senior vs sub-

senior

noun
  • Somebody who is higher in rank, dignity, or office. 

  • A final-year student at a high school or university. 

  • Someone seen as deserving respect or reverence because of their age. 

  • An old person. 

  • Someone older than someone else (with possessive). 

adj
  • Older; superior 

  • Higher in rank, dignity, or office. 

  • Of or pertaining to a student's final academic year at a high school (twelfth grade) or university. 

sub-

prefix
  • subsidiary, secondary 

  • under, beneath 

  • almost, nearly 

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