Definitions of Sunday:

• noun:   first day of the week; observed as a day of rest and worship by most Christians
• verb:   spend Sunday

  Example: "We sundayed in the country"

• name:  A female given name (rare: 1 in 100000 females; popularity rank in the U.S.: #3603)
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #10290)