A genius is a person who displays exceptional intellectual ability, or originality, typically to a degree that is associated with the achievement of new advances in a domain of knowledge. Despite the presence of scholars in many subjects in history, many geniuses have shown high achievements only in a single subject, unlike the talented people. There is no scientifically precise definition of genius, and the question of whether the notion itself has any real meaning has long been a subject of debate, although psychologists are converging on a definition that emphasizes creativity and eminent achievement.

In Roman religion, the genius (; plural genii) is the individual instance of a general divine nature that is present in every individual person, place, or thing. Much like a guardian angel, the genius would follow each man from the hour of his birth until the day he died. For women it was the Juno spirit that would accompany each of them. The Greeks called their genii, daemons, and believed in them long before the Romans.