Jewish calendar

the lunisolar calendar used by Jews, as for determining religious holidays, that is reckoned from 3761 B.C. and was established by Hillel II in the 4th century A.D., the calendar year consisting of 353 days (defective year), 354 days (regular year), or 355 days (perfect year or abundant year) and containing 12 months: Tishri, Heshvan, Kislev, Tevet, Shevat, Adar, Nisan, Iyar, Sivan, Tammuz, Av, and Elul, with the 29-day intercalary month of Adar Sheni added after Adar seven times in every 19-year cycle in order to adjust the calendar to the solar cycle.

The Jewish ecclesiastical year begins with Nisan and the civil year with Tishri. Also called Hebrew calendar. See table under calendar.

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      religious and civil dating system based on both lunar and solar cycles.

      In the Jewish calendar in use today, a day is counted from sunset to sunset, a week comprises seven days, a month contains 29 or 30 days, and a year has 12 lunar months and approximately 11 days (or 353, 354, or 355 days). In order to bring the calendar in line with the annual solar cycle, a 13th month of 30 days is intercalated in the 3rd, 6th, 8th, 11th, 14th, 17th, and 19th years of a 19-year cycle. Therefore, a leap year may total from 383 to 385 days. The Jewish Era in use today was popularly accepted about the 9th century CE and is based on biblical calculations placing the creation in 3761 BCE. (The abbreviations BCE [Before the Common Era] and CE [Common Era] correspond to BC and AD, respectively.)

      The names of the months of the year are derived from Babylonian terms. (Before the Exile, the names were in Hebrew. Only four of them are known today, mentioned in the Bible: Ethanim, Bul, Abib, and Ziv.) The months are ordered according to religious usage and are: Nisan (Abib [March–April of the Western Gregorian calendar]), Iyyar (Ziv [April–May]), Sivan (May–June), Tammuz (June–July), Av (July–August), Elul (August–September), Tishri (Ethanim [September–October]), Ḥeshvan, or Marḥeshvan (Bul [October–November]), Kislev (November–December), Ṭevet (December–January), Shevaṭ (January–February), and Adar (February–March). The 13th month of the leap year, Adar Sheni (or ve-Adar), is intercalated before Adar and so contains the religious observances normally occurring in Adar.

      The civil calendar begins with the month of Tishri, the first day of which is the holiday of Rosh Hashana (“New Year”).

      The Sabbath, the only Jewish holiday enjoined by the Ten Commandments, is observed on the seventh day of the week (Saturday) in commemoration of the seventh day on which God rested after completing the Creation and of God's role in history and his covenant with the Jewish people. Strictly, Jews are obligated to sanctify the Sabbath at home and in the synagogue, to avoid work on that day, and to engage in worship and study.

      The annual cycle of the religious calendar begins with the celebration of Passover (Pesaḥ) on Nisan 15–22. It is one of the so-called major holidays during which work is proscribed, and it is one of the three Pilgrim Festivals that, in ancient times, required all males to attend religious observances at the Temple. Passover is celebrated in remembrance of the Israelites' servitude in Egypt and the subsequent Exodus. The holiday is so named because, on the eve of the Exodus, the homes of the Israelites were “passed over” as God delivered the final of 10 plagues on Egypt.

      The next major holiday of the year is that of Shabuoth ( Shavuot, or Pentecost), celebrated on Sivan 6–7. The second of the Pilgrim Festivals, it commemorates the revelation of the Torah (Law) at Sinai. It is named for the seven weeks of grain harvest that separated Passover from Shabuoth in ancient times.

      The Ten Days of Penitence (yamim noraʾim)—beginning with Rosh Hashana (“New Year”) on Tishri 1–2 and ending with Yom Kippur (“Day of Atonement”) on Tishri 10—are considered the Days of Judgment for all humankind. Strict observance of the prohibition against work and other rules is expected on Rosh Hashana, but celebration is also an important element of the holiday, as indicated by the blowing of the shofar (ram's horn) during the synagogue service. Yom Kippur is the most solemn and holiest day of the Jewish year. Strictly, virtually all of the holiday is to be spent in prayer and fasting; sins are confessed and humankind and God are reconciled. The final prayer service concludes with the sounding of the shofar.

      The last of the major holidays, and the third of the Pilgrim Festivals, is Sukkoth (Sukkot, or “Feast of Tabernacles,” or “Feast of Booths”), which is celebrated on Tishri 15–21 in remembrance of the Israelites' wanderings after the Exodus. This period is marked by joyous celebration and ritual.

      The Jewish religious calendar also includes a series of minor holidays—so called because they are not accompanied by the proscription of work—and fasts. Ḥanukka (Hanukkah) (“Dedication”) commemorates the revolt against the Seleucid ruler Antiochus IV Epiphanes and the rededication of the Temple in 164 BCE. The holiday is celebrated for eight days, beginning on Kislev 25, and is marked by the lighting of candles, feasting, songs, and the giving of gifts to children. Purim (“Feast of Lots”) celebrates the deliverance of Persian Jews from persecution in the 5th century BCE. During this holiday, the Book of Esther is read in the synagogue and feasts, masquerades, and Purim plays are common.

      The five fast days commemorate tragic events in Jewish history. They are Shivaʿ ʿAsar be-Tammuz (Fast of Tammuz (Tammuz, Fast of) 17); Tisha be-Av (Fast of Av 9), which commemorates the destruction of the First and Second Temples in 586 BCE and 70 CE, respectively; Tzom Gedaliahu (Gedaliah, fast of) (Tishri 3); ʿAsara be-Ṭevet (Fast of Ṭevet 10); and Taʿanit Esther (Fast of Esther; Adar 13). Also celebrated are Lag ba-Omer (Lag ba-ʿOmer) (Iyyar 18), usually observed as a school holiday, and Ṭu bi-Shevaṭ (Shevaṭ 15), in modern times associated with the planting of trees in Israel.

      Since the establishment of the modern state of Israel in 1948, three other holidays have been added to the Jewish calendar. They are Holocaust Day (Nisan 27), Remembrance Day (Iyyar 4), and Independence Day (Iyyar 5).

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