Sisig's name was written in
cuneiform as
si-si-ig. Like other theonyms, it was usually prefaced by the
determinative dingir, though exceptions where it is omitted are known. He was also known under the
Akkadian name Zaqīqu. Ziqīqu is attested as a variant form. In addition to phonetic spellings, in Akkadian AN.ZA.GAR3 (usually read as
Zagar) could function as a
logogram meant to be read as Zaqīqu. Sisig was regarded as a god of dreams. However, other dream deities are also attested, for example
Mamu.
Iškar Zaqīqu, an eleven tablet compendium of
oneiromancy written in Akkadian known from the
library of Ashurbanipal, was named after the Akkadian form of Sisig's name. The Akkadian form of the name, if written without the
dingir sign, could also refer to ghosts, though this meaning is not attested for the Sumerian form. Furthermore,
zaqīqu can also be translated as "puff of air" instead depending on context. The translation "emptiness" has also been proposed. However, according to
Andrew R. George the word was only used to refer to emptiness or nothingness metaphorically, which parallels similar use of
šāru, "wind". Anette Zgoll suggests that the use of Zaqīqu as a name of a god of dreams might be derived from a possible belief that a person's
zaqīqu ghost represented them in dreams, both their own and those of others. However, it has also been argued that Sisig was primarily understood as a ghost-like
underworld god, and his association with dreams was a secondary development. George assumes that the use of
zaqīqu to refer to ghosts and a dream god reflected the perception of ghosts and entities associated with dreams as equally intangible as a gust of wind. Enrico Marcato notes that while in
Hatra in the late first millennium BCE Zaqīqā, a derivative of
zaqīqu, is attested as a theonym, it seemingly functioned as a generic designation for
deified ancestors, since in a single case it is used to describe two individuals presumed to be deceased members of a single family, presumably worshiped in a small shrine. In addition to sources from Hatra, this term might occur in similar context in contemporary texts from
Dura-Europos, and earlier on in theophoric names from the
Neo-Assyrian period, such as Bar-zāqê. ==Associations with other deities==