While it is agreed that the two primary names of the Mesopotamian moon god, Nanna and Sin (Suen), originated in two different languages, respectively Sumerian and Akkadian, it is not possible to differentiate between them as designations of separate deities, as they effectively fully merged at an early date.

[3] Gebhard J. Selz [de] points out this phenomenon is already attested in sources from Lagash from the Early Dynastic period, where the name Nanna does not appear, and Sin is the form used in both Sumerian and Akkadian context.

[1] In later periods LAK-32 coalesced with ŠEŠ (the ideogram for "brother"), and Nanna's name came to be written as dŠEŠ+KI or dŠEŠ.KI, though phonetic spellings such as na-an-na are attested too, for example as glosses in lexical lists.

[13] It is uncertain if the theonym Nanum attested in a theophoric name from Umma is a derivative of Nanna, while Nanni worshiped in Mari and in the kingdom of Khana was a female deity and might be related to Nanaya rather than the moon god.

[19] However, Manfred Krebernik [de] concludes that no certain cognates of Sin's name have been identified in other Semitic languages, and syn (or sn), who according to him is only known from Thamudic inscription from Hadhramaut, should instead be interpreted as Sayin, the local sun god.

[15] From the Old Babylonian period onward Sin's name could be represented by the logogram d30 (𒀭𒌍), derived from the cuneiform numeral 30, symbolically associated with him due to the number of days in the lunar month.

[28] Piotr Steinkeller notes that it is not impossible both proposals regarding the meaning of Dilimbabbar are correct, and that the scribes might have intentionally created puns depending on the well attested tradition of referring to the moon as a unique or solitary celestial body.

[56] Sin could also function as a divine judge in the underworld,[57] as attested for example in the so-called First Elegy of the Pushkin Museum, in which a man named Ludingira hopes that he will proclaim a good verdict for his deceased father.

[65] An Old Babylonian literary composition written in Sumerian describes Sin as the head of the divine assembly (Ubšu’ukkin),with Anu, Enlil, Inanna, Utu, Enki and Ninhursag serving as his advisers.

[73] She suggests both Nabonidus and Ashurbanipal relied on so-called "Theology of the Moon", a concept well attested in explanatory texts from the first millennium BCE according to which Sin possessed divine powers (Sumerian ĝarza, Akkadian parṣū) equal to these of Anu, Enlil and Ea during the first half of the lunar month.

[91] It has been argued that an Early Dynastic text from Abu Salabikh already refers to Enlil and Ninlil as his parents, though an alternate view is that he oldest certain evidence only goes back to the reign of Ur-Nammu of the Third Dynasty of Ur.

[123] Due to identification with Inanna, the Hurrian and Elamite goddess Pinikir is referred to as a daughter of Sin and Ningal in a text written in Akkadian but found in a corpus of Hurro-Hittite rituals.

[133] Nin-MAR.KI, who was traditionally regarded as Nanshe's daughter, is also placed in the section of An = Anum dedicated to Sin, though according to Walther Sallaberger her presence there might reflect her well attested association with cattle, which she shared with the moon god.

[144] However, Steve A. Wiggins states that despite the connection between Sin and Yarikh the latter shows a number of traits distinct from his counterpart, for example literary texts at times compare him to a dog, an animal not associated with the Mesopotamian moon god.

[3] A bilingual Akkadian-Kassite lexical list indicates that the Kassite deity regarded as the counterpart of Sin was Ši-ḪU (reading of the second sign uncertain), well attested as an element of theophoric names, though he was more commonly equated with Marduk in similar sources.

[153] Ur was already well established as the cult center of the moon god, initially under his Sumerian name Nanna, in Early Dynastic times, as attested in the Zame Hymns from Abu Salabikh.

[160] An inscription from this period refers to him as one of the major members of the pantheon, next to Enlil, Ninlil, Inanna, Enki, Nergal, Ninurta, Nuska, Ninshubur and the deified hero Gilgamesh, included in the enumeration due to his importance for the ruling house.

[189] During his reign the Edublamaḫ, "house, exalted door socket", originally a court of law dedicated to Sin build by Shu-Ilishu to commemorate the return of a statue of this god from Anshan, was rebuilt as a temple.

[8] Little is known about the worship of Sin in Ur during the reign of the Second Dynasty of Isin and beyond, as no late temple archive has been discovered, and the information is limited to scarce archeological evidence for building activity and a small number of commemorative inscriptions.

[200] Paul-Alain Beaulieu notes that his investigation of the nature of the office of en priestess in the previous periods of Mesopotamian history can be compared to a degree to the work of a modern archeologist.

[227] Coins from the mint established in Harran in the late fourth century BCE under the rule of Antigonus I Monophthalmus are marked with a crescent, which is presumed to be an indication of continuation of the worship of Sin.

[254] While Sin was seemingly not actively worshiped in Early Dynastic Lagash, he appears among the deities invoked in an oath formula on the Stele of the Vultures, as well as in both Sumerian and Akkadian theophoric names identified in sources from this area, such as Amar-Suen and Puzur-Suen.

[262] Sin played an important role in the Diyala basin, for example in an inscription of Dadusha of Eshnunna enumerating the major deities of his kingdom he is listed directly after Anu and Enlil, which is a position where usually Enki (Ea) would be expected to appear.

[267] Sin is also the most commonly occurring god in personal names known from tablets from the Chogha Gavaneh site in western Iran, which in the early second millennium BCE was an Akkadian settlement most likely connected to the kingdom of Eshnunna.

[268] While in Babylonia sanctuaries dedicated to Sin were typically located in cities associated with deities regarded as his relatives, for example his father Enlil in the case of Nippur and his daughter Ishtar in Uruk and Babylon, in Assyria they occur mostly in settlements which served as this region's capitals at various points in time.

[30] After a hymnic prologue praising Nippur, the narrative relays how Sin dispatches his servants to provide him with wood from various areas, including Ebla and Tummal, so that he can have a ship constructed to that end.

[263] In Inanna's Descent Ninshubur, the sukkal (attendant deity) of the eponymous goddess, is tasked with petitioning Nanna, as well as Enlil and Enki,[290] in order to prevent her mistress from dying in the underworld.

[293] Dina Katz argues that a direct parallel to this passage can be found in the myth Gilgamesh, Enkidu and the Netherworld and on this basis suggests an intertextual relation between these two compositions.

[295] However, Alhena Gadotti disagrees with Katz's proposal and argues that evidence for a connection between the two texts is lacking, and the passages are not directly parallel as Gilgamesh, Enkidu and the Netherworld notably does not feature Nanna.

[10] However, while it is agreed that a part of the local population was neither Christian nor Muslim, according to Blömer it should be called into question if their practice reflected the ancient worship of Sin in any meaningful capacity.