The term demigod or demi-god can refer to a minor deity, a mortal who is the offspring of a god and a human being, or a figure who has attained divine status after death.
The English term "demigod" is a calque of the Latin semideus, "half-god", which was probably coined by the Roman poet Ovid in reference to less important gods, such as dryads.
In the ancient Greek and Roman world, the word did not have a consistent definition and was rarely used.
The earliest recorded use of the term is by the archaic Greek poets Homer and Hesiod. Both describe dead heroes as hemitheoi, or "half gods". In these cases, the word did not mean that these figures had one parent who was divine and one who was mortal. Instead, those who demonstrated "strength, power, good family, and good behavior" were termed heroes, and after death they could be called hemitheoi, a process that has been referred to as "heroization".Pindar also used the term frequently as a synonym for hero.
According to the Roman author Cassius Dio, Julius Caesar was declared a demigod by the Roman Senate after his victory at Thapsus. However, Dio was writing in the third century — centuries after the death of Caesar — and modern critics have cast doubt on whether the Senate really did this.
The first Roman to employ the term demigod may have been the poet Ovid, who used the Latin semideus several times in reference to minor deities.The poet Lucan also uses the term to speak of Pompey attaining divinity upon his death. In later antiquity, the Roman writer Martianus Capella proposed a hierarchy of gods as follows: the gods proper, or major gods; the genii or daemones; the demigods or semones (who dwell in the upper atmosphere); the manes and ghosts of heroes (who dwell in the lower atmosphere); and the earth-dwelling gods like fauns and satyrs.