Nicolosi is an Italian surname that originates from the town of Nicolosi, a comune (municipality) in the Metropolitan City of Catania on the island of Sicily. The town itself was named after Saint Nicholas, the fourth-century Christian saint known for his generosity and gift-giving traditions. Thus, the surname Nicolosi is a topographic and patronymic name, indicating someone who came from or lived in Nicolosi, a settlement dedicated to Saint Nicholas. Place of Origin The town of Nicolosi lies on the southern slopes of Mount Etna, Europe's highest active volcano. Its name in Sicilian is Niculusi. The municipality borders several other towns, including Adrano, Belpasso, Biancavilla, Bronte, and Castiglione di Sicilia, among others, reflecting its location in a region rich with historic settlements. Its history is closely tied to Sicily's agrarian culture and the volcanic activity of Etna, which has both enriched the soil and posed recurring challenges. Notable Bearers A prominent bearer of the Nicolosi surname in contemporary history is Joseph M. Nicolosi (1934–2025), an American clinical psychologist and founder of the Thomas Aquinas Psychological Clinic in Encino, California. He was known for his controversial work on conversion therapy, a topic that sparked public debate about sexual orientation and therapy. Another well-known figure is Salvatore Nicolosi (1922–2022), the Roman Catholic Bishop of Lipari (Sacerdoti del S. Cuore) and a distinguished figure in Italian ecclesiastical history. The surname Nicolosi is also carried by various artists, including Frank Nicolosi, a mid-20th century American actor known for his roles in film and television, and A. Frank Nicolosi, who similarly served as an actor. From Italy, painter Emilio Nicolosi (activities circa 17th–18th century, exact dates often incomplete) left artworks bound predominantly---the historical regions of Syracuse. Meaning: From the town of Nicolosi, Sicily; named for Saint Nicholas Type: Topographic and patronymic surname Origins: Southern Italy, especially Sicily Usage Regions: Predominantly Italy; diaspora globally, especially U.S.