day by day vs nightly

day by day

adv
  • one day at a time 

  • gradually 

nightly

adj
  • Happening or appearing in the night; night-time; nocturnal. 

  • Performing, occurring, or taking place every night. 

  • Used in the night. 

noun
  • A build of a software program with the latest changes, released every night. 

adv
  • Every night. 

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