hour vs working day

hour

noun
  • A time period of sixty minutes; one twenty-fourth of a day. 

  • A season, moment, or time. 

  • The time. 

  • Used after a two-digit hour and a two-digit minute to indicate time. 

  • The set times of prayer, the canonical hours, the offices or services prescribed for these, or a book containing them. 

  • A distance that can be traveled in one hour. 

working day

noun
  • The part of a day in which work is done; the number of hours one must work per day for a specified wage. 

  • Any of those days of a week on which work is done, officially Monday to Friday in many countries (even though many people work on weekends). 

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