Sunday

Sunday is traditionally the first day of the Judaeo-Christian seven-day week , between 1 Saturday and Monday, and the second day of the weekend in some cultures. It is considered a holiday in lands of Christian tradition, and is the day when most Christians attend Chruch .
In India, Sunday is Ravivar . It is based on Ravi - Vedic God of Sun.

The name Sunday

In ancient Jewish tradition Saturday is the Sabbath , a day of worship on which abstinence from work is required. The first Christians were Jews and maintained the observance of the Jewish Sabbath rest, but by the first half of the second century most Christians no longer observed the Sabbath, instead gathering for worship on Sunday (although for some time the Sabbath continued to be held in a special regard even among Christians who observed Sunday).
The majority of Christians have continued to observe Sunday ever since, although throughout history one sometimes finds Christian groups that continued or revived the observance of the Saturday Sabbath. More recently in history, Christians in the Seventh day Adventist , Seventh day Baptist and Chruch of God(Seventh-Day) denominations (along with many related or similar sects), as well as many Messianic Jews, have revived the practice of gathering for worship, and abstaining from work, on the Saturday Sabbath.
Many languages lack separate words for "Saturday" and "Sabbath". Eastern Orthodox churches, as well as many Roman Catholics , distinguish between the Sabbath (Saturday) and Sunday, which most Christians traditionally call the Lord's Day . However, many Protestants and Roman Catholics refer to Sunday as the Sabbath, though tshis is by no means a universal practice among Protestants and Catholics.

The name "Sunday" (Day of the Sun) apparently originated in pre-Christian Egyptian culture. (See Herbert Thurston's article "Christian Calendar" in the 1908 Catholic Encyclopedia.) In Egyptian astrology, the seven planets , Saturn, Jupiter, Mars, the Sun, Venus, Mercury, and the Moon, each had an hour of the day assigned to them, and the planet which was "regent" during the first hour of any day of the week gave its name to that day. The Egyptian form of the seven-day week spread from Egypt to Rome during the first and second century, when the Roman names of the planets were given to each successive day. Germanic-speaking nations apparently adopted the seven-day week from the Romans, so that the dies Solis became Sunday (German, Sonntag).
The first Christian reference to Sunday is found in the First Apology of St. Justin Martyr (circa 150 A.D.). In a well-known passage of the Apology, Justin describes the Christian custom of gathering for worship on Sunday. "And on the day called Sunday, all who live in cities or in the country gather together to one place . . .", he writes. Evidently Justin used the term "Sunday" because he was writing to a non-Christian, pagan audience. In Justin's time, Christians usually called Sunday the Lord's Day (because they observed it as a weekly memorial of Jesus Christ's resurrection) or "the Eighth Day" (because of the Christian belief that Christ's resurrection on the day following the seventh-day Sabbath is a portal to timeless eternity that transcends the seven-day weekly cycle).