about time vs then

about time

adv
  • Close to the right time. 

  • Far past the desired time. 

  • Used other than figuratively or idiomatically: see about, time. 

then

adv
  • At that time. 

  • Next in order of place. 

  • In addition; also; besides. 

  • At the same time; on the other hand. 

  • Used to contradict an assertion. 

  • In that case. 

  • Soon afterward. 

noun
  • That time 

adj
  • Being so at that time. 

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