α Piscis Austrini (Latinised to Alpha Piscis Austrini) is the system's Bayer designation.
It also bears the Flamsteed designation of 24 Piscis Austrini.
The classical astronomer Ptolemy put it in Aquarius, as well as Piscis Austrinus.
In the 1600s Johann Bayer firmly planted it in the primary position of Piscis Austrinus.
Following Ptolemy, John Flamsteed in 1725 additionally denoted it 79 Aquarii.
The current designation reflects modern consensus on Bayer's decision, that the star belongs in Piscis Austrinus.
Under the rules for naming objects in multiple star systems, the three components – Fomalhaut, TW Piscis Austrini and LP 876-10 – are designated A, B and C, respectively.
On its discovery, the planet was designated Fomalhaut b.
The star's traditional name derives from Fom al-Haut from scientific Arabic فم الحوت  fam al-ḥūt (al-janūbī) "the mouth of the [Southern] Fish" (literally, "mouth of the whale"), a translation of how Ptolemy labeled it.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars.
The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included the name Fomalhaut for this star.

In July 2014, the International Astronomical Union (IAU) launched a process for giving proper names to certain exoplanets.
The process involved public nomination and voting for the new names.
In December 2015, the IAU announced the winning name was Dagon for this planet.
The winning name was proposed by Todd Vaccaro and forwarded by the St. Cloud State University Planetarium of St. Cloud, Minnesota, United States of America, to the IAU for consideration.
Dagon was a Semitic deity, often represented as half-man, half-fish.
α Piscis Austrini (Latinised to Alpha Piscis Austrini) is the system's Bayer designation. It also bears the Flamsteed designation of 24 Piscis Austrini. The classical astronomer Ptolemy put it in Aquarius, as well as Piscis Austrinus. In the 1600s Johann Bayer firmly planted it in the primary position of Piscis Austrinus. Following Ptolemy, John Flamsteed in 1725 additionally denoted it 79 Aquarii. The current designation reflects modern consensus on Bayer's decision, that the star belongs in Piscis Austrinus. Under the rules for naming objects in multiple star systems, the three components – Fomalhaut, TW Piscis Austrini and LP 876-10 – are designated A, B and C, respectively. On its discovery, the planet was designated Fomalhaut b.
The star's traditional name derives from Fom al-Haut from scientific Arabic فم الحوت  fam al-ḥūt (al-janūbī) "the mouth of the [Southern] Fish" (literally, "mouth of the whale"), a translation of how Ptolemy labeled it. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included the name Fomalhaut for this star.
In July 2014, the International Astronomical Union (IAU) launched a process for giving proper names to certain exoplanets. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Dagon for this planet. The winning name was proposed by Todd Vaccaro and forwarded by the St. Cloud State University Planetarium of St. Cloud, Minnesota, United States of America, to the IAU for consideration. Dagon was a Semitic deity, often represented as half-man, half-fish.
Fomalhaut