- Easter Sunday is the most important day in the Christian calendar.
- Low Sunday, first Sunday after Easter, is also known as the Octave of Easter, White Sunday, Quasimodo Sunday, Alb Sunday, Antipascha Sunday, and Divine Mercy Sunday.
- Palm Sunday is the Sunday before Easter.
- On March 7, 321, Constantine I decreed that Sunday will be observed as the “Roman day of Rest.”
- In Judaism and Islam Mondays are considered auspicious days for fasting.
- In Judaism the Torah is read in public on Monday mornings, and special penitential prayers are said on Monday, unless there is a special occasion for happiness which cancels them.
- In the Eastern Orthodox Church Mondays are days on which the Angels are commemorated.
- Easter Monday is the day after Eastern Sunday and is celebrated as a holiday in some largely Christian cultures, especially Roman Catholic cultures.
- In the Eastern Orthodox Church, Tuesdays are dedicated to Saint John the Baptist.
- According to the Hebrew Bible, Wednesday is the day when the Sun and Moon were created.
- Ash Wednesday, the first day of Roman Catholic Lent, occurs forty days before Easter, not counting Sundays.
- Spy Wednesday is an old name given to the Wednesday immediately proceeding Easter, in allusion to the betrayal of Jesus by Judas Iscariot.
- In the Hindu religion, from Guru, the Sanskrit name for Jupiter, the largest of planets. Guruvaar fasting is very common throughout India for various holy/religious reasons.
- In Judaism and Islam Thursdays are considered auspicious days for fasting.
- In Judaism the Torah is read in public on Thursday mornings, and special penitential prayers are said on Thursday.
- Maundy Thursday is the Thursday before Easter — the day on which the Last Supper occurred.
- Ascension Thursday is 40 days after Easter, when Christ ascended into Heaven.
- In the Eastern Orthodox Church, Thursdays are dedicated to the Apostles and Saint Nicholas.
- In the United States, Thanksgiving Day is an annual festival celebrated on a Thursday in November, currently the fourth Thursday.
- The Jewish Sabbath begins at sunset on Friday and lasts until nightfall on Saturday.
- In Christianity Good Friday is the Friday before Easter. It commemorates the crucifixion of Jesus.
- Traditionally, Roman Catholics were obliged to refrain from eating the meat of land animals on Fridays.
- Some Traditionalist Catholics voluntarily continue to practice every-Friday abstinence.
- Some Anglo-Catholics also practice abstinence either on all Fridays or on Fridays in Lent.
- The Eastern Orthodox Church continues to observe Fridays as fast days throughout the year (with the exception of several fast-free periods during the year.
- Orthodox also abstains from using oil in their cooking and from alcoholic beverages. For the Orthodox, Fridays throughout the year commemorate the Crucifixion of Christ and the Mother of God.
- In Islam, Friday is the day of public worship in mosques.
- Friday is also the day of rest in the Bahá’í Faith.
- Good Friday is the Friday before Easter in the Christian calendar. It commemorates the crucifixion of Jesus.
- Black Friday refers to any one of several historical disasters that happened on Fridays.
- Adventist, Seventh-day Baptist, Church of God, Messianic Jews observe Saturdays as their Sabbath day.