The toponym derives from the name of a settlement in Guria called აჭი(ač̣i), root of which is believed to be replicated in აჭარა(ač̣ara).
According to the more widespread hypothesis proposed by Pavle Ingorokva the root of აჭარა(ač̣ara) goes back to the endonym ჭანი(č̣ani), an ancient Kartvelian tribe ancestral to modern Mingrelians and Lazs. Ingorokva also reconstructs earlier *აჭანრა(ač̣anra), a circumfixed form of the same root meaning "the place where Chans dwell".
The more recent theory narrows down the root to *ჭ(č̣), indicating correspondence to the Kartvelian *წყალ-(“water”). This supposition is accepted by Bedoshvili, but he considers *ჭარ(č̣ar) to be the root instead, arguing the fact that this root regularly corresponds to *წყალ-(“water”) in many dialects of the Georgian language.
Ačaṙean, Hračʻeay (1977) “հաճար”, in Hayerēn armatakan baṙaran [Armenian Etymological Dictionary] (in Armenian), 2nd edition, a reprint of the original 1926–1935 seven-volume edition, volume III, Yerevan: University Press, page 16a
Čubinašvili, Niḳo (1812–1825) “აჭარა”, in Kartuli leksiḳoni rusulis targamaniturt [Georgian Explanatory Dictionary with Russian Commentaries][2], Saint Petersburg: Imperial Academy of Sciences