Various scholars identify it either with the modern Hadjiavat, or with Slava Rusă. The inscription consists of two fragments with texts in Greek and Latin, whose content is not identical. The hydronym appears twice in the Latin part of the inscription (ISM I, № 68).

The name Gabranus was identified as Thracian in the first publication of the inscription by V. Pârvan in 1916. D. Detschew includes it in Die thrakischen Sprachreste without commenting on the suggested etymology. I. Russu also considers the name to be Thracian, while V. Georgiev – to be Dacian, and according to both of them, it has the same etymology meaning “deep.” L. Franga defines the hydronym as Dacian, as well, but with a different etymology, believing that the river name Κέβρος/ Κίαβρος in Thracian stems from the same root. V. N. Toporov includes it in the list of Thraco-Baltic parallels, comparing it with Latv. Gabris, Gabrani etc., but also with Bulg. Gabrovo.

A number of researchers consider the hydronym to be Celtic: S. Lambrino, V. Velkov and I. Duridanov associate it with the Celtic appellative gabro- ‘goat’ and the Celtic settlement names Gabromagus, Gabrosentum and Gabranus. However, experts in Celtic studies, such as L. Franga and A. Falileev doubt the Celtic origin of Gabranus for strictly phonological reasons. The latter also notes that there is not a single example of a Celtic river name in the Balkans. Although there are several Celtic settlement names in the Danube delta region (Noviodunum, Arrubium, Aliobrix), there are none in the Histria region.

The great variety of attempts at etymologising and finding both the linguistic affiliation and related names in other languages is due to the lack of data on the common nouns from which the names are derived. There are no sound arguments to support the assumption that Gabranus and Κέβρος originated from the same root, as we know nothing about the semantics of both hydronyms. The connection with the name of the Bulgarian city of Gabrovo, which, like many other settlement and river names, derives from the Proto-Slavic *grabrъ, as suggested by some scholars, is also not possible.

Gabranus will remain one of the names with a disputed origin. Although there are no other names with this root in the entire Thracian linguistic area, it cannot be excluded from the corpus of Thracian names due to the geographical location of the river and the strong objections of L. Franga and A. Falileev regarding a probable Celtic origin.