lunchtime vs noontime

lunchtime

noun
  • The time or hour at or around which lunch is normally eaten. 

  • A break in work or school to eat lunch. 

noontime

noun
  • Approximately noon. 

  • Noon. 

  • The time at which something peaks in some way (e.g., in vitality, in influence, in reknown) (by analogy with the waxing of the sun each day). 

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