Mothering Sunday is a Christian festival celebrated throughout Europe that falls on the 4th Sunday in Lent. Secularly it became an occasion for reuniting with your family and giving flowers, cakes and gifts to your mother. It is increasingly being called Mother's Day, although that holiday has other origins. In the UK it is considered synonymous with Mother's Day as celebrated in other countries.

During the sixteenth century, people returned to their mother church, the main church or cathedral of the area, for a service to be held on Laetare Sunday. This was either a large local church, or more often the nearest Cathedral. Anyone who did this was commonly said to have gone "a-mothering", although whether this preceded the term Mothering Sunday is unclear. In later times, Mothering Sunday became a day when domestic servants were given a day off to visit their mother Church, usually with their own mothers and other family members. It was often the only time that whole families could gather together, since on other days they were prevented by conflicting working hours.

Sunday (ⁱ/ˈsʌndeɪ/ or /ˈsʌndi/) is the day of the week between Saturday and Monday. For most Christians, Sunday is observed as a day for worship of God and rest, due to the belief that it is Lord's Day, the day of Christ's resurrection.

Sunday is a day of rest in most Western countries, part of 'the weekend'. In most Muslim countries, and Israel, Sunday is a working day.

According to the Hebrew calendars, traditional Christian calendars, Sunday is literally the "first day" of the week. According to the International Organization for Standardization ISO 8601 Sunday is the seventh and last day of the week.

No century in the Gregorian calendar starts on a Sunday, whether its first year is '00 or '01. The Jewish New Year never falls on a Sunday. (The rules of the Hebrew calendar are designed such that the first day of Rosh Hashanah will never occur on the first, fourth, or sixth day of the Jewish week; i.e., Sunday, Wednesday, or Friday).

The English noun Sunday derived sometime before 1250 from sunedai, which itself developed from Old English (before 700) Sunnandæg (literally meaning "sun's day"), 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, Icelandic sunnudagur and Swedish söndag). The Germanic term is a Germanic interpretation of Latin dies solis ("day of the sun"), which is a translation of the Ancient Greek heméra helíou. The p-Celtic Welsh language also translates the Latin "day of the sun" as dydd Sul.