Jewish holidays are observed according to the Hebrew calendar, and Israeli law requires state institutions to include the Hebrew date on official letters and public notices. Yet most Israelis conduct their daily lives according to the Gregorian calendar, running from January to December. Religious and traditional Jews sometimes lament the dominance of what Israelis commonly call the “foreign” calendar. But how Hebrew is the Hebrew calendar itself? The answer is more complicated than it might seem.
The names of the months now regarded as Hebrew were actually adopted from Babylonian culture. Most originated in Akkadian, an ancient Semitic language related to Hebrew. At least one of them poses an especially striking problem from a Jewish perspective: Tammuz was the name of a fertility god worshipped in Mesopotamian religions, including Babylonian and Sumerian traditions.
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The names of the months were influenced by weather and the seasons
(Photo: Jose Hernandez Camera 51 / Shutterstock)
“There’s something amusing about people raising an eyebrow, for example, when children are named July. Tammuz, after all, is the name of a Sumerian god,” said Dr. Esther Haber of Bar-Ilan University’s Department of Hebrew Language and Semitic Languages. “Adar, Nisan, Iyar and Sivan are also Akkadian names. Akkadian resembles Hebrew because it is a Semitic language, but these are essentially foreign names.”
The names have become deeply embedded in Israeli culture. According to the Central Bureau of Statistics, thousands of Israelis born between the establishment of the state and 2024 were given names taken from the Hebrew calendar.
Sivan was by far the most common, with 11,034 people bearing the name. Another 4,083 were named Adar, 2,545 Nisan and 1,002 Iyar. There were also 119 people named Tammuz, 49 named Av, 41 Elul, 13 Tevet, nine Tishrei and seven Shevat. The figures showed no Israelis named Marcheshvan, or its shortened form Heshvan, nor anyone named Kislev.
In many parts of the Bible, months are identified simply by number under an older system in which Nisan was considered the first month.
Earlier biblical texts preserve only three named months: “the month of Bul,” identified as the eighth month and corresponding to Marcheshvan; “the month of Ethanim,” the seventh month, corresponding to Tishrei; and “the month of Ziv,” the second month, corresponding to Iyar. Those are ancient Canaanite names.
Only in later biblical books, including Zechariah, Esther, Ezra and Nehemiah, do some of the familiar Babylonian-derived names begin to appear.
(Twelve Months | Lyrics and music by Naomi Shemer)
So when did Jews begin using the names that today run from Tishrei through Elul? “This system came into use when the exiles from the first Babylonian exile returned to the Land of Israel in the sixth century BCE, during the Return to Zion,” Haber said. “They were the elite, scribes and court officials, and they were literate. They encountered these month names while living in Babylon, adopted them and brought them here.”
That created an obvious religious problem: How could Jews use Babylonian names, including Tammuz, which was associated with a form of pagan worship explicitly forbidden by Judaism?
Rabbis and Jewish scholars wrestled with the question over the centuries. Nachmanides, the medieval Spanish Jewish scholar also known as Ramban, explained that the Torah had instructed Jews to count the months beginning with Nisan as a reminder of the Exodus from Egypt. After the Babylonian exiles returned, he argued, they adopted the Babylonian month names to commemorate their second redemption.
“We will thus recall through the months the second redemption, just as until now we recalled the first,” he wrote.
Some later commentators suggested that the word Tammuz in the Book of Ezekiel could refer to heat or burning rather than the deity. But the straightforward reading is that the text refers to the god.
An explanation attributed to Rabbi Chaim Kanievsky addressed the problem more directly. The Mishnah says that on the 17th of Tammuz, an idol was erected in the Temple. According to the explanation, the sages may have accepted use of the Babylonian name because it could itself serve as a reminder of that calamity and inspire repentance.
The common mistake about Marcheshvan
The meanings of some month names remain uncertain, while others can be traced with greater confidence. Tishrei comes from the Akkadian word tashritu, meaning “beginning” or “start.”
“In ancient times, it had not yet been settled whether the year should begin in spring or autumn,” Haber said. “Eventually, we settled on beginning the year in autumn.”
(Tishrei Song | Lyrics by Rachel Shapira, music by Dani Amihud)
Marcheshvan, the following month, preserves the opposite system, in which the year was counted from Nisan. Its name derives from the Akkadian expression warah shamnu, meaning “the eighth month.”
Haber explained that in later Babylonian speech, the sounds represented by the letters corresponding to the Hebrew vav and mem could interchange. Over time, the original meaning of the name was forgotten, and Hebrew speakers began treating it as if it consisted of two separate parts, mar and Heshvan.
That eventually produced the common shortened form Heshvan. It also gave rise to a popular folk explanation that the prefix mar, meaning “bitter” in Hebrew, was added because the month contains no Jewish festival. Linguistically, however, that explanation is incorrect.
The meaning of Kislev is less clear. Its Akkadian form was Kislimu. Many of the other month names appear to reflect nature and seasonal weather. Tevet derives from the Akkadian Tebetu, apparently connected to a verb meaning “to sink.” The name may refer to the wet weather typical of the period, when people and objects could sink into water or mud.
Shevat may also be connected to rain. Its name is thought to derive from the Akkadian Shabatu, meaning “to strike,” “beat” or “lash,” perhaps referring to pounding winter rains.
Flooding in southern Israel
(Photo: Oren Ravid / Shutterstock)
Adar was not always a happy month
Jewish tradition famously teaches, “When Adar begins, we increase our joy.” Its original name, however, may have carried almost the opposite meaning.
According to Haber, the Akkadian name Adaru appears to have developed from an older form associated with being dark or gloomy.
“By that period, the Babylonians apparently no longer pronounced the sound corresponding to the Hebrew het, so they called the month Adaru, but fundamentally the name was Hadaru,” she said. “‘Hadar’ means ‘gloomy.’”
The name may have referred to the cloudy skies typical of that time of year. Nisan, called Nisannu in Akkadian, referred to the first produce of trees and fields and may be related to the Hebrew word nitzan, meaning bud.
The origin of Iyar, Ayaru in Akkadian, remains uncertain. Some have proposed a connection to a word meaning light. The meaning of Sivan, from the Akkadian Simanu, is also unclear, although it has been linked to a word meaning an appointed time or fixed date.
A party in a Tel Aviv shelter during last Purim
(Photo: AFP)
The women who mourned Tammuz
Then there is Tammuz. In Sumerian, the god was known as Dumuzi, a name that can be translated as “faithful son.” Babylonian mythology held that Tammuz descended each year into the underworld at the height of summer, then returned to life in autumn as vegetation began to grow again.
His wife in Sumerian mythology was Inanna, the “Queen of Heaven,” a goddess also associated with fertility. She corresponds to the Akkadian goddess Ishtar, and the two traditions appear eventually to have merged.
As plants withered in the summer heat, worshippers would mourn Tammuz’s death. The practice is explicitly mentioned in Ezekiel 8:14, where the prophet describes “women sitting there, mourning Tammuz” at the entrance to the Temple in Jerusalem.
The scene appears as part of a catalogue of acts condemned by Ezekiel as abominations, making clear the prophet’s hostility toward pagan worship at Judaism’s holiest site.
(It’s Sad to Die in the Middle of Tammuz | Lyrics and music by Naomi Shemer)
The ancient myth later found its way into modern Hebrew poetry. In his 1909 poem “The Death of Tammuz,” Hebrew poet Shaul Tchernichovsky invoked the pagan story, calling on the “daughters of Zion” to mourn Tammuz and imagining the coming days of cloud and premature autumn.
Nathan Alterman also drew on the myth in his early poem “December,” referring to those “killed by the Tammuzes,” apparently suggesting that the rainy winter month restored strength to those who had struggled through the hot, dry summer.
(December | Lyrics by Nathan Alterman, music by Moshe Wilensky)
Naomi Shemer, whose work often drew on the rhythms of the Hebrew calendar, was likewise influenced by Tchernichovsky’s treatment of the myth. Before undergoing surgery, fearing that she might not wake from the procedure, she wrote “In the Middle of Tammuz,” remembered for the line, “It is sad to die in the middle of Tammuz.” Shemer herself later died on the seventh day of Tammuz in the Hebrew year 5764.
Giving Babylonian names a Jewish meaning
The original meaning of Av, Abu in Akkadian, remains uncertain. It may be related to a word meaning harvest, although another theory connects it to reeds. Elul, originally Ululu in Akkadian, is similarly difficult to decipher.
But like Marcheshvan, Elul was later given a new meaning through Jewish folk etymology. Jewish sages famously interpreted its Hebrew letters as an acronym for the biblical phrase Ani ledodi vedodi li, “I am my beloved’s and my beloved is mine.”
(Tammuz Band – End of the Orange Season | Lyrics by Meir Ariel, music by Ariel Zilber and Shalom Hanoch)
Marcheshvan and Elul were far from the only months to receive such reinterpretations. Rabbi Menachem Mendel Kasher, in his work Torah Shelemah, cited a Yemenite Jewish midrash preserved in manuscripts that assigns explicitly Jewish meanings to each of the Babylonian names.
Nisan, it said, was so named because miracles, nisim in Hebrew, were performed for Israel during the month. Iyar was linked to the manna given to the Israelites in the desert. Sivan was connected to Mt. Sinai and miracles.
Tammuz was associated with the sin of the Golden Calf and with idolatry. Av was described as a “father of calamity.” Elul was interpreted positively, while Tishrei was linked to an Aramaic phrase meaning to forgive and pardon sins.
Marcheshvan was connected to the completion of the First Temple, Kislev to the constellation Orion, Tevet to good done for Israel, Shevat to lashing rain and Adar to greatness and the birth of Moses.
It was one of many attempts over the centuries to effectively “Judaize” names inherited from Babylon by giving them Hebrew or Jewish explanations.
The repeated effort suggests that generations of Jewish sages were not entirely comfortable with the foreign origins of the calendar’s familiar names. Rather than abandon them, they reinterpreted them, weaving words inherited from ancient Babylon into the history, values and religious memory of the Jewish people