The etymology of the name is unknown, but apparently not Semitic. A folk etymology in Hebrew is that, when the ocean was created, it expanded until it reached Acre and then stopped, giving the city its name. (In Hebrew, ad koh means "up to here" and no further.)
Acre seems to be recorded in Egyptian hieroglyphics, possibly being the "Akka" in the execration texts from around 1800 BC and the "Aak" in the tribute lists of Thutmose III (1479–1425 BC). The Akkadian cuneiform Amarna letters also mention an "Akka" in the mid-14th-century BC. On its native currency, Acre's name was written ʿK (Phoenician: 𐤏𐤊). It appears in Assyrian and once in Biblical Hebrew. Other transcriptions of these names include Acco, Accho, Akke, and Ocina.
Acre was known to the Greeks as Ákē (Greek: Ἄκη), a homonym for Greek word meaning "cure". Greek legend then offered a folk etymology that Hercules had found curative herbs at the site after one of his many fights. This name was latinized as Ace. Josephus's histories also transcribed the city into Greek as Akre.
Under the successors of Alexander the Great, the Egyptians called the city Ptolemais (Greek: Πτολεμαΐς, Ptolemaΐs) and the Syrians Antioch (Greek: Ἀντιόχεια, Antiókheia) or Antiochenes. As both names were shared by a great many other towns, they were variously distinguished. The Syrians called it "Antioch in Ptolemais" (Ἀντιόχεια τῆς ἐν Πτολεμαΐδι, Antiókheia tôs en Ptolemaΐdi), and the Romans Ptolemais in Phoenicia. Others knew it as "Antiochia Ptolemais" (Ἀντιόχεια Πτολεμαΐς, Antiókheia Ptolemaΐs).
Under Claudius, it was also briefly known as Germanicia in Ptolemais (Γερμανίκεια τῆς ἐν Πτολεμαΐδι, Germaníkeia tôs en Ptolemaΐdi). As a Roman colony, it was notionally refounded and renamed Colonia Claudii Caesaris Ptolemais or Colonia Claudia Felix Ptolemais Garmanica Stabilis after its imperial sponsor Claudius; it was known as Colonia Ptolemais for short.
During the Crusades, it was known again as Acre or as St. John of Acre (French: St.-Jean d'Acre), after the Knights Hospitaller who had their headquarters there.