The name Nellia is thought to have originated from the Latin word "nebula," which means "mist" or "cloud." It is believed to have been derived as a feminine form of the name Nello, which was a medieval Italian name. The earliest recorded use of the name Nellia dates back to the late 12th century in parts of northern Italy and southern France.

One of the earliest known historical references to the name Nellia can be found in a medieval Italian text from the 13th century, which mentions a woman by the name of Nellia di Firenze, who was a renowned seamstress and textile merchant in Florence. Another notable early reference is from a 14th-century French manuscript that records a Nellia de Bordeaux, who was a respected scholar and translator.

During the Renaissance period, the name Nellia gained some popularity among the Italian nobility. One of the earliest recorded examples is Nellia Sforza (1472-1535), who was a member of the powerful Sforza family and served as the Countess of Santa Fiora. Another prominent figure was Nellia Orsini (1546-1611), a Roman noblewoman and patron of the arts.

In the 17th century, the name Nellia spread to other parts of Europe, particularly in France and England. One notable example is Nellia de Rohan (1628-1700), a French noblewoman and courtier at the court of Louis XIV. In England, there was Nellia Fiennes (1673-1720), a notable travel writer and explorer who undertook extensive journeys across Europe and Asia.

The 19th century saw the emergence of several influential women with the name Nellia, including Nellia Bly (1864-1922), an American journalist and pioneering investigative reporter known for her record-breaking trip around the world in 72 days. Another notable figure was Nellia Trent (1842-1925), a British suffragist and activist who campaigned for women's rights and educational reform.