The surname DEFONZO is of Italian origin and can be traced back to the late 15th century. It is believed to have originated from the southern region of Campania, particularly in the area around Naples. The name is derived from the Italian phrase "de Fonzo," meaning "from Fonzo."

Fonzo is thought to be a reference to an old place name or a medieval feudal estate. Some historians suggest that it may have been a corruption of the Latin word "fons," meaning "fountain" or "spring." This could indicate that the original bearers of the name lived near a notable water source or that the name was associated with a specific location known for its natural springs.

One of the earliest known references to the name can be found in a document from 1492, which mentions a certain "Giovanni de Fonzo" residing in the town of Caserta, near Naples. This document, which recorded property transactions, suggests that the name was already well-established in the region by that time.

In the 16th century, records show a few notable individuals bearing the DEFONZO surname. One such person was Gian Battista DeFonzo, a scholar and poet born in Naples around 1520. He was known for his contributions to Renaissance literature and his works were widely circulated throughout Italy during his lifetime.

Another notable figure was Tommaso DeFonzo, a military commander who served under the Spanish Viceroy of Naples in the late 1500s. He played a significant role in the defense of the city during the Ottoman siege of 1558 and was celebrated for his bravery and strategic leadership.

In the 17th century, the name appears to have spread to other parts of Italy, with records showing individuals named DEFONZO residing in cities like Rome and Florence. One such individual was Antonio DeFonzo, a renowned painter and sculptor born in Rome in 1645. His works, which often depicted religious themes, can be found in various churches and galleries across Italy.

As the centuries passed, the DEFONZO name continued to be carried by individuals of note. In the 19th century, Giuseppe DeFonzo was a renowned composer and conductor from Naples who contributed significantly to the development of Italian opera. He was born in 1823 and died in 1899.

Another notable DEFONZO was Vincenzo DeFonzo, a lawyer and politician born in Campania in 1856. He served as a member of the Italian Parliament and was instrumental in advocating for legal reforms and social changes during his time in office.

While the DEFONZO surname has its roots in southern Italy, it has since spread to other parts of the world due to immigration. However, its historical significance and ties to the Campania region remain an integral part of its heritage.