The English words “orgy” and “erotic” have their origins in Greek and in ancient Greece they were associated with mystery religions.
While the concept of “orgy” today brings up images of unbridled sex, sexuality, and sexual intercourse, the origins of the word do not involve sex. Reaching far back in time, we see that “orgy” has its origins in the Indo-European root *werg- which means “to do.” The English word “work” also comes from this stem.
The Greek word “orgia”, meaning “secret rites, worship”, comes from the Indo-European *worg- which is a variation of *werg-. Among the Greeks, “orgia” was used in reference to the rites practiced in the worship of deities such as Orpheus and Dionysus. “Orgia” did not describe sexual activity, though sex was a part of some of the ceremonies.
In ancient Greece, there were four basic kinds of religion: (1) the civic religion, (4) household religions, (3) philosophic religions, and (4) mystery religions. The “orgias” were a part of the mystery religions which were open only to initiates, unlike the public religions of this time and the private household religions. While sexuality and fertility were concerns, the primary goal of the “orgia” was to achieve an ecstatic union with the divinity.
“Orgia” passed into Latin and then into Old French, and finally landed in English in 1589 as “orgy” which was used to described the secret rites of the Greek and Roman religions. In the next few centuries, the religious meaning of the word disappeared and it now was used to describe sexual activities.
The Greek god Eros is the personification of passionate love. According to Greek tradition, Eros was the son of Hermes (the messenger god) and Aphrodite (the goddess of love). The Greeks worshipped Eros as a god of fertility and installed statues of him in their gymnasiums. As a god of fertility, Eros presided over sexual love as the ancient Greeks realized that having children involved sexual intercourse.
Aphrodite would intervene mischievously in the affairs of gods and mortals, causing bonds of love to form. In pre-classical Greece, the cult of Eros was less important than that of Aphrodite. Later, in Athens, he shared a popular cult with Aphrodite and the fourth day of every month was sacred to him.
The English word “erotic” comes from the Greek via the French word “érotique.”
Note: the * indicates that the Indo-European or prehistoric word has been reconstructed by historical linguists.