*Deh₂nu
*Deh₂nu- is a hypothetical goddess of water in Proto-Indo-European mythology, with connections to the names of rivers like the Danube, Don, Dnieper, and Dniester, as well as the Vedic deity Dānu, the Irish Danu, and the Welsh Dôn. Despite acknowledging a possible lexical connection, Mallory and Adams contend that there is not enough evidence to support the idea that a distinct river goddess existed in Proto-Indo-European beliefs. They primarily highlight the Indic tradition's understanding of river deification. Furthermore, Mallory and Adams suggest that a theory for a sea god called *Trih₂tōn—whose name is derived from the Greek Triton and the Old Irish word for sea, trïath—is unsupported by the lack of a corresponding sea god in Irish mythology and only minor lexical similarities. The Ossetian god Donbettyr is also mentioned in the story. Who is placated by gifts to keep the waterwheel turning, and who Donnán of Eigg proposes as a Christian equivilent of this figure.
Moreover, this deity and the Dan river in Centeral Asia may have similar etymologies.
She is frequently seen as the mother of a mythical tribe, the *Deh₂newyóes, in many Indo-European cultures; these tribes are deduced from the Vedic Danavas, the Irish Tuatha Dé Danann, the Greek Danaoi, and the Norse Danes. Under Bel's leadership, this tribe is said to have fought a hero called *H₂nḗrtos, which could connect them to characters like the Norse god Njord, the Nart from the Nart saga, and Indra's epithet nrtama.