Neo-Latin is the style of written Latin used in original literary, scholarly, and scientific works, first in Italy during the Italian Renaissance of the fourteenth and fifteenth centuries, and then across northern Europe after about 1500, as a key feature of the humanist movement. Through comparison with Latin of the Classical period, scholars from Petrarch onwards promoted a standard of Latin closer to that of the ancient Romans, especially in grammar, style, and spelling. The term Neo-Latin was however coined much later, probably in Germany in the late 1700s, as Neulatein, spreading to French and other languages in the nineteenth century. Medieval Latin had diverged quite substantially from the classical standard and saw notable regional variation and influence from vernacular languages. Neo-Latin attempts to return to the ideal of Golden Latinity in line with the Humanist slogan ad fontes.

Classical Latin is the form of Literary Latin recognized as a literary standard by writers of the late Roman Republic and early Roman Empire. It formed parallel to Vulgar Latin around 75 BC out of Old Latin, and developed by the 3rd century AD into Late Latin. In some later periods, the former was regarded as good or proper Latin; the latter as debased, degenerate, or corrupted. The word Latin is now understood by default to mean "Classical Latin"; for example, modern Latin textbooks almost exclusively teach Classical Latin.