Tanit, or Tanith, is the Great Goddess of Carthage, worshipped there as its chief Deity. She is a Sky Goddess who ruled over the Sun, Stars, and Moon; and as a Mother Goddess She was invoked for fertility. The palm tree is Hers, as the desert version of the Tree of Life; and as symbolic of the life-force of the Earth the serpent is Hers as well—in fact Her name means "Serpent Lady".
Tanit is identified with both Ashtart (Astarte) and Athirat, and Her other symbols include the dove, grapes and the pomegranate (both symbolic of fruitfulness and fertility), the crescent moon, and, like Ashtart, the lion.
Carthage was a city of the Phoenician colony in northern Africa, not far from the modern city of Tunis in Tunisia. Carthage, the Roman rendition of the Phoenician name Karthadasht, which means "New Town", was founded in around the 9th century BCE, by Dido ("Giver" or "Grantor [of prayers]", or alternately "Wanderer") or Elissa (from the Phoenician Elishat), the daughter of the King of Tyre in Roman legend. Dido, however, being also used as an epithet of the Phoenician Moon-Goddess, is probably to be considered an aspect of or alternate name for Tanit, the patron Goddess of Carthage. Worship of Tanit dates to the 5th century BCE, and it is unsure whether Tanit was a local deity adapted by the Phoenician colonists or a version of Ashtart/Athirat they had brought with them from Phoenicia.
Tanit was the highest Deity of that city, called "the Lady of Carthage". With Her consort Ba'al-Hammon, the God of the Sky, She watched over and protected Carthage. As a protective Deity She had some martial aspects, and like Ashtart could be depicted riding a lion holding a spear or long sceptre. In Carthage She was said to have an Oracle; perhaps this is connected to Her role as Star-Goddess.
Tanit has Her own abstract symbol, peculiarly Hers (and accordingly called the "symbol of Tanit"): a triangle with a circle at the top, with a horizontal line between the two; sometimes two additional vertical bars come from the ends of the horizontal. This has been interpreted as either a stylization of an altar, or a woman or Goddess in a long dress, Her arms upraised in an attitude of worship or blessing. Some stelae do show a more realistic depiction of the Goddess in this attitude, so my money is on it as an abstract depiction of a woman. This symbol is found all over Carthage, though there is only one example of it in Phoenicia itself.
Tanit was identified with Aphrodite, Demeter, and Artemis by the Greeks and with Juno by the Romans, especially their Juno Lucina, Goddess of Light and Childbirth. The Romans also associated Her with the Magna Mater, the Great Mother, Rhea or Cybele.
Source: Obscure Goddesses