Tishrei is the first month in the current way of counting, and the seventh month counting from the Exodus from Egypt.
Tishrei is the Babylonian name which our forefathers brought with them upon their return from Babylonia.
The source of the name “tishrei” is to be found in the Acadian language, in which “tashreytu” means “beginning”, since it is the first of the months of the year.
According to tradition, it was in Tishrei that the world was created.
In the Torah, the month is termed “the seventh month”, as it is written: “In the seventh month, on the first of the month, it shall be a Sabbath for you, a memorial of blowing of horns, a holy occasion.” (Leviticus XXIII, 24).
In the prophetical literature, it is called “Eithanim”. “And all the men of Israel assembled themselves to king Solomon at the feast in the month Eithanim, which is the seventh month” (I Kings VIII, 2).
The sages, of blessed memory, commented on the name “Eithanim” (mighty ones).
According to Rabbi Eliezer, the patriarchs who are “mighty ones of the world” were born in this month. The sages, of blessed memory, further commented: “It is called ‘the seventh (shevi’i from the root: shin-beit-ayyin) month’ because it is full (mesubba’ from the root: sin-beit-ayyin) of everything; in it the wine-vats are full, in it there are blessings, there is atonement in it, there is the festive booth, the palm-branch and the willow in it.” (Midrash Rabba Leviticus XXIX, 8).