SIVAN (Heb. סִיוָן), the post-Exilic name of the third month of the Jewish year. Occurring in the Bible and in the Apocrypha (Esth. 8:9; i Bar. 1:8) and frequently in rabbinic literature (as in Megillat Ta'anit), the name is held to be etymologically connected with samu or asamu ("to mark" or "to appoint" in Assyrian, akin to sim in Hebrew). The zodiacal sign for this month is Gemini. In the present fixed Jewish calendar, it invariably consists of 30 days, the First of Sivan never falling on Monday, Thursday, or the Sabbath (see *Calendar). In the 20th century Sivan in its earliest occurrence extends from May 11th to June 9th and in its latest from June 9th to July 8th.
Historical anniversaries in Sivan comprise: 1. Third–Fifth of Sivan, the "Three Days of the Bounds" commemorating the three-days' preparation for the revelation on Mount Sinai (Ex. 19:10–16); 2. Sixth of Sivan (in the Diaspora also Seventh of Sivan), *Shavuot (the festival of Weeks); 3. Seventh, fifteenth, and sixteenth of Sivan, anniversaries of Hasmonean victories (Meg. Ta'an. 3); 4. Twenty-fifth of Sivan, Israel's defeat of Ishmael, Canaan, and Egypt in a contest adjudicated by Alexander the Great (ibid.); (7, 8, 9) Twenty-third, twenty-fifth, and twenty-seventh of Sivan, once observed as fasts (ibid., 13; Tur and Sh. Ar. oḤ 580) commemorating Jeroboam i's suspension of pilgrimages to Jerusalem and the martyrdom of the tannaim, *Simeon b. Gamaliel i, *Ishmael b. Elisha, *Hananiah Segan ha-Kohanim, and *Hananiah b. Teradyon.
[Ephraim Jehudah Wiesenberg]