Contributed by: R. Ezra Mizrahi
Tammouz is the fourth month counting from Nisan, and is referred to as the fourth month in various places in the Tanakh. The month is not referred as Tammouz throughout the Tanakh.
Where did the name Tammouz come from?
Similar to the other names of the other Hebrew months, the name Tammouz originated in Babylonia (Bavel). The name had been associated with a Babylonian pagan cult, as the verse (YehezqeI 8:14) states: And behold the women sat there and caused Tammouz to cry.
וַיָּבֵא אֹתִי אֶל פֶּתַח שַׁעַר בֵּית ה' אֲשֶׁר אֶל הַצָּפוֹנָה וְהִנֵּה שָׁם הַנָּשִׁים יֹשְׁבוֹת מְבַכּוֹת אֶת הַתַּמּוּז
As Rashi explains, Tammouz was the name of an Avoda Zara in Bavel, where the women of the cult used to ignite the large idol from the inside. The eyes of the idol were made from lead, and as the temperature inside the idol increased, condensation formed on the eyes on the outside. The women would then claim that Tammouz was crying for offerings. This is why the verse states that they caused Tammouz to cry. Being that our nation spent many years in the exile of Babylonia, influence of the culture in the religion was pervasive. Consequentially, the name Tammouz was incorporated as the name of a month on the Hebrew calendar.