The site of the ruin-mound of Shaddai is called Tell eth-Thadyen, "Thadyen" being the modern Arabic rendering of the original West Semitic "Shaddai". It has been conjectured that El Shaddai was therefore the "god of Shaddai". According to Exodus 6:2, 3, Shaddai was the name by which God was known to Abraham, Isaac and Jacob. Shaddai thus being associated in tradition with Abraham, the inclusion of the Abraham stories into the Hebrew Bible may have brought the northern name with them, according to the Documentary hypothesis of the origins of the Hebrew Bible.
In the vision of Balaam recorded in the Book of Numbers 24:4 and 16, the vision comes from Shaddai along with El. In the fragmentary inscriptions at Deir Alla, though Shaddai is not, or not fully present, shaddayin appear, less figurations of Shaddai. These have been tentatively identified with the ŝedim of Deuteronomy 34:17 and Psalm 106:37-38, who are Canaanite deities.
The name Shaddai (Hebrew: שַׁדַּי) is used as an epithet of El later in the Book of Job.
In the Septuagint and other early translations Shaddai was translated with words meaning "Almighty". The root word "shadad" (שדד) means "to overpower" or "to destroy". This would give Shaddai the meaning of "destroyer" as one of the aspects of God. Thus it is essentially an epithet. Harriet Lutzky has presented evidence that Shaddai was an attribute of a Semitic goddess, linking the epithet with Hebrew šad "breast" as "the one of the Breast", as Asherah at Ugarit is "the one of the Womb".
Another theory is that Shaddai is a derivation of a Semitic stem that appears in the Akkadian shadû ("mountain") and shaddā`û or shaddû`a ("mountain-dweller"), one of the names of Amurru. This theory was popularized by W. F. Albright but was somewhat weakened when it was noticed that the doubling of the medial d is first documented only in the Neo-Assyrian period. However, the doubling in Hebrew might possibly be secondary. In this theory God is seen as inhabiting a mythical holy mountain, a concept not unknown in ancient West Asian mythology (see El), and also evident in the Syriac Christian writings of Ephrem the Syrian, who places Eden on an inaccessible mountaintop.
An alternative view proposed by Albright is that the name is connected to shadayim which means "breasts" in Hebrew. It may thus be connected to the notion of God’s fertility and blessings of the human race. In several instances it is connected with fruitfulness: "May God Almighty [El Shaddai] bless you and make you fruitful and increase your numbers…" (Gen. 28:3). "I am God Almighty [El Shaddai]: be fruitful and increase in number" (Gen. 35:11). "By the Almighty [El Shaddai] who will bless you with blessings of heaven above, blessings of the deep that lies beneath, blessings of the breasts [shadayim] and of the womb [racham]" (Gen. 49:25).
It is also given a Midrashic interpretation as an acronym standing for "Guardian of the Doors of Israel" (Hebrew: שׁוֹמֶר דְלָתוֹת יִשְׂרָאֶל), which is commonly found as carvings or writings upon the mezuzah, a vessel which houses a scroll of parchment with Biblical text written on it, that is situated upon all the door frames in a home or establishment.