mid- vs on-

mid-

prefix
  • Amid. 

  • Denoting the middle part. 

  • Occupying a middle position. 

  • Intermediate 

  • During, in the middle of doing something. 

on-

prefix
  • on, at, toward, upon. 

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