Sabbath (/ˈsæbəθ/) is a day set aside for rest and worship. According to Exodus 20:8 the Sabbath is commanded by God to be kept as a holy day of rest, as God rested from creation. It is observed differently among the Abrahamic religions and informs a similar occasion in several other practices. Although many viewpoints and definitions have arisen over the millennia, most originate in the same textual tradition of: "Remember the sabbath day, to keep it holy".
In Judaism, Sabbath is the seventh day of the Hebrew calendar week, which in English is known as Saturday. The term has been used to describe a similar weekly observance in any of several other traditions; the first crescent or new moon; any of seven annual festivals in Judaism and some Christian traditions; any of eight annual pagan festivals (usually "sabbat"); an annual secular holiday; and a year of rest in religious or secular usage, the sabbath year, originally every seventh year.
Shabbat[edit]
Jewish Shabbat (Shabbath, Shabbes, Shobos, etc.) is a weekly day of rest, observed from sundown on Friday until the appearance of three stars in the sky on Saturday night; it is also observed by a minority of Christians like Messianic Judaism, and The Seventh Day Adventists-S.D.A. Thirty-nine activities prohibited on Shabbat are listed in Tractate Shabbat (Talmud). Customarily, Shabbat is ushered in by lighting candles shortly before sunset, at halakhically calculated times that change weekly and geographically.
Judah ha-Levi (12th century) proposed a nascent Jewish date line for dating of Shabbat, later calculated to fall between China and Japan (other lines exist, and travelers are expected to note both personal and local Shabbat); and Pinchas Elijah Horovitz (18th century) stated that polar regions should observe Shabbat based on calculating 24-hour days, although without establishing a date line.
Shabbat is a widely noted hallmark of Jewish peoples. Subbotniks (literally, Sabbatarians) are a Russian sect, categorized as either Jews or Judaizing Christians, that became particularly branded by strict Shabbat observance; (Hungarian-born radical Reform leader Ignaz Einhorn even shifted his congregation's Shabbat worship to Sundays.) Several weekly Shabbats per year are designated as Special Sabbaths, such as Shabbat haGadol, prior to Pesach (literally, "the High Sabbath", but not to be confused with other High Sabbaths); and Shabbat Teshuvah, prior to Yom Kippur ("Repentance Sabbath").
Shabbaton[edit]
Colloquially, in contemporary Israel, the term Shabbaton or Shaboson means an event or program of education and usually celebration held on Shabbat, or over an entire weekend with main focus on Shabbat. Such events are held by youth groups, singles groups, synagogues, schools, social groups, charitable groups or family reunions, can be either multi-generational and wide-open or limited-group, and can be held where a group usually meets or offsite. "Shabbaton", rather than just "retreat", signifies recognition of the importance of Shabbat in the event or program.
above content from:
http://socialvocabulary.com/defines/sabbath
and Wikipedia.com