From Latin 'hilaris' meaning cheerful or happy.
Hillary traces its origins to the Latin hilarius, meaning "cheerful" or "merry," which itself descends from the Greek hilaros. The name was made famous in the early Christian tradition by Saint Hilary of Poitiers (c. 315–367 AD), a theologian and bishop who vigorously defended orthodox Nicene Christianity against Arianism and was exiled for his beliefs — a man who was anything but merely jolly.
The English legal and academic terms "Hilary term" (the January–April term at Oxford, Cambridge, and the Inns of Court) derive directly from his feast day on January 13, embedding the name into centuries of British institutional life. For much of its history, Hillary was used for both men and women in Britain, crossing the gender line with the freedom that medieval naming conventions sometimes allowed. S.
Senator, Secretary of State, and presidential candidate — becoming by far its most globally recognized bearer. Her decades in public life gave Hillary a particular political valence: a name associated with ambition, resilience, controversy, and groundbreaking achievement simultaneously. Sir Edmund Hillary, the New Zealand mountaineer who co-summited Everest in 1953, kept the male variant alive and added connotations of high-altitude audacity.
Hillary's popularity crested in the United States in the 1960s and 1970s and has declined sharply since — a fate common to many names closely associated with a single public figure. Yet its roots remain beautiful: a name that literally means joy, worn by fighters and climbers, lawyers and saints.