The name Eloisa has its origins in the medieval French language and culture, stemming from the Old French name Heloise or Heloïse. It is a variant of the Germanic name Hadelouge, which combines the elements "hadu" (battle) and "lug" (famous).

The name gained significant prominence in the 12th century through the tragic love story of the French philosopher Peter Abelard and his student Heloise. Their forbidden love and eventual marriage, despite Abelard's castration by Heloise's uncle, became one of the most celebrated romantic tales of the Middle Ages.

The earliest recorded instance of the name Eloisa appears in the letters exchanged between Abelard and Heloise, which were widely circulated and transcribed across Europe, ensuring the name's enduring legacy. These letters, along with their biographies, remain treasured works of medieval literature.

One of the most famous individuals bearing the name Eloisa was Eloisa de Lusignan (1195-1244), a French noblewoman and the wife of King Peter I of Cyprus. Known for her beauty and intelligence, she played a crucial role in the political affairs of the Kingdom of Cyprus during the 13th century.

Another notable Eloisa was Eloisa Orsini (1339-1382), an Italian noblewoman and the wife of Galeazzo II Visconti, the Lord of Milan. She was celebrated for her patronage of the arts and her support of the construction of the Visconti Castle in Pavia.

In the realm of literature, the name Eloisa found immortality in Alexander Pope's celebrated poem "Eloisa to Abelard" (1717), which poetically reimagined the tragic love story of Abelard and Heloise, further cementing the name's association with passionate and ill-fated romance.

Another notable Eloisa was Eloisa Marquez de Bassauri (1756-1835), a Venezuelan educator and pioneer in women's education. She established one of the first schools for girls in Caracas and was recognized for her efforts in promoting education during the colonial era.

The name Eloisa has also been borne by several fictional characters, including Eloisa in the novel "La Vida es Sueño" by the Spanish playwright Pedro Calderón de la Barca, further contributing to its literary and cultural significance.