mid- vs sub-

mid-

prefix

  • Amid. 

  • Denoting the middle part. 

  • Occupying a middle position. 

  • Intermediate 

  • During, in the middle of doing something. 

sub-

prefix

  • under, beneath 

  • subsidiary, secondary 

  • almost, nearly 

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