Saturday vs Sunday

Saturday

noun
  • The seventh day of the week in many religious traditions, and the sixth day of the week in systems using the ISO 8601 norm; observed as the Sabbath/Shabbat in Judaism (Friday sunset to Saturday sunset); it follows Friday and precedes Sunday. 

adv
  • On Saturday. 

Sunday

noun
  • The first day of the week in many religious traditions, and the seventh day of the week in systems using the ISO 8601 standard; the Christian Sabbath; the Lord's Day; it follows Saturday and precedes Monday. 

  • A comic strip published in a Sunday newspaper. 

  • A newspaper published on Sunday. 

adv
  • On Sundays. 

verb
  • To spend Sunday (at a certain place, with a certain person or people, etc.). 

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