The same name Astibus (with the variant Istubera) was also borne by a settlement located on the river, today the town of Štip.

The name was defined as Thracian by V. Tomaschek. D. Detschew also accepts the name as Thracian, only pointing out as a possible parallel the Asia Minor settlement name Ἀστίβια.

The name is difficult to analyse, since only one testimony is available and it is unclear whether it is related to the names with the root Ἀστ- (the tribal name Ἀσταί, the settlement name Ἀστακός, the personal name Ἀστικóσης) or, as Tomaschek suggests, a- can be understood as a prefix. The etymology is unclear.