Adad in Akkadian and Ishkur in Sumerian and Hadad in Aramaic are the names of the storm-god in the Babylonian-Assyrian pantheon. All three are usually written by the logogram dIM. The Akkadian god Adad is cognate in name and functions with northwest Semitic god Hadad.
In Akkadian, Adad is also known as Ramman ("Thunderer") cognate with Aramaic Rimmon which was a byname of the Aramaic Hadad. Ramman was formerly incorrectly taken by many scholars to be an independent Babylonian god later identified with the Amorite god Hadad.
The Sumerian Ishkur appears in the list of gods found at Fara but was of far less importance than the Akkadian Adad later became, probably partly because storms and rain are scarce in southern Babylonia and agriculture there depends on irrigation instead. Also, the gods Enlil and Ninurta also had storm god features which decreased Ishkur's distinctiveness. He sometimes appears as the assistant or companion of one or the other of the two.
When Enki distributed the destinies, he made Ishkur inspector of the cosmos. In one litany Ishkur is proclaimed again and again as "great radiant bull, your name is heaven" and also called son of An, lord of Karkara; twin-brother of Enki, lord of abundance, lord who rides the storm, lion of heaven.
In other texts Adad/Ishkur is sometimes son of the moon god Nanna/Sin by Ningal and brother of Utu/Shamash and Inana/Ishtar. He is also occasionally son of Enlil.
Adad/Ishkur's consort (both in early Sumerian and later Assyrian texts) was Shala, a goddess of grain, who is also sometimes associated with the god Dagan. She was also called Gubarra in the earliest texts. The fire god Gibil (named Gerra in Akkadian) is sometimes the son of Ishkur and Shala.
Adad/Ishkur's special animal is the bull. He is naturally identified with the Anatolian storm-god Teshub. Occasionally Adad/Ishkur is identified with the god Amurru, the god of the Amorites.
The Babylonian center of Adad/Ishkur's cult was Karkara in the south, his chief temple being E. Karkara; his spouse Shala his was worshipped in a temple named E. Durku. But among the Assyrians his cult was especially developed along with his warrior aspect. From the reign of Tiglath-Pileser I (1115–1077 BCE), Adad had a double sanctuary in Assur which he shared with Anu. Anu is often associated with Adad in invocations. The name Adad and various alternate forms and bynames (Dadu, Bir, Dadda) are often found in the names of the Assyrian kings.
Adad/Ishkur presents two aspects in the hymns, incantations, and votive inscriptions. On the one hand he is the god who, through bringing on the rain in due season, causes the land to become fertile, and, on the other hand, the storms that he sends out bring havoc and destruction. He is pictured on monuments and cylinder seals (sometimes with a horned helmet) with the lightning and the thunderbolt (sometimes in the form of a spear), and in the hymns the sombre aspects of the god on the whole predominate. His association with the sun-god, Shamash, due to the natural combination of the two deities who alternate in the control of nature, leads to imbuing him with some of the traits belonging to a solar deity.
Shamash and Adad became in combination the gods of oracles and of divination in general. Whether the will of the gods is determined through the inspection of the liver of the sacrificial animal, through observing the action of oil bubbles in a basin of water or through the observation of the movements of the heavenly bodies, it is Shamash and Adad who, in the ritual connected with divination, are invariably invoked. Similarly in the annals and votive inscriptions of the kings, when oracles are referred to, Shamash and Adad are always named as the gods addressed, and their ordinary designation in such instances is bele biri ("lords of divination").