Sunday is considered a non-working day in many countries of the world, and are part of "the weekend". Countries predominantly influenced by Jewish or Islamic religions have Friday or Saturday as a weekly non-working day instead.
The English noun Sunday derived sometime before 1250 from sunedai, which itself developed from Old English (before 700) Sunnandæg (literally meaning "day of the sun"), which is cognate to other Germanic languages, including Old Frisian sunnandei, Old Saxon sunnundag, Middle Dutch sonnendach (modern Dutch zondag), Old High German sunnun tag (modern German Sonntag), and Old Norse sunnudagr (Danish and Norwegian søndag, and Swedish söndag). The Germanic term is a Germanic interpretation of Latin dies solis ("day of the sun"), which is a translation of of Greek heméra helíou.
In most of the Indian Languages, the word for Sunday is or Ravivar, Adivar and It'var, with Adi (Ah'-Dee) or Ravi being the Sanskrit names for the Sun. The first Christian reference to Sunday is found in the First Apology of St. Justin Martyr (c. 150 AD). In a well-known passage of the Apology (Chapter 67), Justin describes the Christian custom of gathering for worship on Sunday. "And on the day called Sunday [τῇ τοῦ ῾Ηλίου λεγομένη ἡμέρᾳ], all who live in cities or in the country gather together to one place, and the memoirs of the apostles or the writings of the prophets are read, as long as time permits . . .", 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).
Sunday has also been called "the Eighth Day" (because of the Roman Catholic 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).
A number of languages appear to reflect Sunday's status as the first day of the week. In Greek, the names of the days Monday, Tuesday, Wednesday, and Thursday (Δευτέρα, Τρίτη, Τετάρτη, and Πέμπτη) mean "second", "third", "fourth", and "fifth", respectively. This suggests that Sunday was once counted as Πρώτη, that is, "first". The current Greek name for Sunday, Κυριακή, means "Lord's Day". A similar system of naming days of the week occurs in Portuguese. Monday is segunda-feira, which means "second day", also showing Sunday (domingo) to be counted as the first day. Similarly modern Latin uses "feria secunda" for Monday.
Slavonic languages use day-numbers that implicitly number Monday as 1, not 2. For example, Polish has czwartek (4) for Thursday and piątek (5) for Friday. [Hungarian péntek (Friday) is a cognate of this, although, Hungarian not being a Slavonic or even Indo-European language, the correlation with "5" is not evident to a Hungarian speaker].
Christians from very early times have had differences of opinion on the question of whether the Sabbath should be observed on a Saturday or a Sunday. The issue does not arise for Jews, for whom the Shabbat is unquestionably on Saturday, nor for Muslims whose day of assembly (jumu'ah) is on a Friday.
The first evidence of a differentiation from the traditional Jewish Shabbat observance, and the religious observance of the first day of the week, appears in Acts 20:7 where the disciples met to participate in the ordinance of the sacrament. Col 2:16 also demonstrates that the early Christians were beginning to differ from their Jewish neighbors, not only in the new tradition of eating foods that had been prohibited under Judaism, but also in their observance of the Sabbath day. The Apostle John also refers to the "Lord's Day" in Rev 1:10 - indicating that those to whom he was writing were familiar with the term. Some early Jewish Christians observed the Sabbath on Saturday, but by the first half of the second century an increasing number of Christians would gather for worship on Sunday. Some continued to observe the Sabbath on Saturday, until even the crusader period. The practice was discouraged, but not suppressed.
Though some Christians use the decree in support of the move of the Sabbath day to Sunday, in fact the decree was in support of the worship of the Sun-God (see Sol Invictus). In any event, the decree did not apply to Christians or Jews. It was part of the Roman civil law and religion and not an edict of the Church.
Many Christians today consider Sunday to be the Sabbath day, a holy day and a day of rest and church-attendance. Denominations which observe Saturday as the Sabbath are called Sabbatarians; however, the name Sabbatarian has also been claimed by Christians, especially Protestants, who believe Sunday must be observed with just the sort of rigorous abstinence from work associated with the Jewish Sabbath (exemplified by Eric Liddell as depicted in the film Chariots of Fire). For most Christians the custom and obligation of Sunday rest has not been as strict.
In Orthodox Christian families and communities, some activities are not done, e.g. working, doing something that requires somebody else to work such as buying goods or services (including the use of public transport), driving a car, gardening, washing a car, etc. Exceptions which are allowed are making use of religious services, and, usually, using electricity, and urgent medical matters. In Russian, the word for Saturday is Subota ("Sabath"). In Roman Catholicism, those who work in the medical field, in law enforcement, or soldiers in a war zone are dispensed from the usual obligation to avoid work on Sunday.
The majority of Christians have continued to observe the Sabbath on 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 Church of God (Seventh-Day) denominations (along with many related or similar denominations), as well as many Messianic Jews, have revived the practice of abstaining from work and gathering for worship on Saturdays.
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 some Christians traditionally call the Lord's Day (). However, many Protestants and Roman Catholics do refer to Sunday as the Sabbath, though this is by no means a universal practice among Protestants and Catholics. Quakers traditionally refer to Sunday as "First Day" eschewing the pagan origin of the English name.
In Roman Catholicism liturgy, Sunday begins on Saturday evening. The evening Mass on Saturday is liturgically a full Sunday Mass and fulfils the obligation of Sunday Mass attendance, and Vespers (evening prayer) on Saturday night is liturgically 'first Vespers' of the Sunday. The same evening anticipation applies to other major solemnities and feasts, and is an echo of the Jewish practice of starting the new day at sunset (so that Sabbath starts on the Friday night).
In the Eastern Orthodox Church, Sunday begins at the Little Entrance of Vespers (or All-Night Vigil) on Saturday evening and runs until "Vouchsafe, O Lord" (after the prokeimenon) of Vespers on Sunday night. During this time, the dismissal at all services begin with the words, "May Christ our True God, who rose from the dead…". Anyone who wishes to receive Holy Communion at Divine Liturgy on Sunday morning is required to attend Vespers the night before (see Eucharistic discipline). Among Orthodox Christians, Sunday is considered to be a "Little Pascha" (Easter), and because of the Paschal joy, the making of prostrations is forbidden, except in certain circumstances. The Russian The word for Sunday is Voskresenie, meaning "Resurrection day". In Greek the word for Sunday is Kyriake (the "Lord's Day").
The Polish word for Sunday (niedziela) can be translated as "without acts (work)"
In the United States and Canada, National Basketball Association and National Hockey League games, which are usually played at night during the week, are frequently played during daytime hours - often broadcast on national television. Major League Baseball usually schedules all Sunday games in the daytime except for the nationally televised Sunday Night Baseball matchup. Certain historically religious cities such as Boston and Baltimore among others will schedule games no earlier than 1:35 PM to ensure time for people who go to religious service in the morning can get to the game in time.
In the UK, some club and Premier League football matches and tournaments usually take place even Rugby matches and tournaments usually take place in club grounds or parks on Sunday mornings. It is not uncommon for church attendance to shift on days when a late morning or early afternoon game is anticipated by a local community.
Also in the United States, many federal government buildings are closed on Sunday. Privately owned businesses also tend to close or are open for shorter periods of the day than on other days of the week.
Many American, Australian and British television networks and stations also broadcast their political interview shows on Sunday mornings.
In Ireland, Gaelic football and hurling matches are predominantly played on Sundays, with the second and fourth Sundays in September always playing host to the All-Ireland hurling and football championship finals, respectively.
North American Radio stations often play specialty radio shows such as Casey Kasem's countdown or other nationally syndicated radio shows that may differ from their regular weekly music patterns on Sunday morning and/or Sunday evening.