Apparently Hippo Regius (ʿpwn, 𐤏𐤐𐤅𐤍) derived its name from the word ûbôn that means harbour in Punic, but I can't find it in a dictionary. The more modern French name Bône or Bona of the current city (Annaba), was derived from Ubbo, a local version of the long forgotten ancient Punic and Latin names of the city. Hippo Diarrhytus had the same Punic name ʿpwn (𐤏𐤐𐤅𐤍) as Hippo Regius and the two cities had to be called differently by both Greeks and Romans. The source for ûbôn is page 326 of the book Through the Eye of a Needle: Wealth, the Fall of Rome, and the Making of Christianity in the West, 350–550 AD by the historian Peter Brown.