One of the most popular of the Roman gods was Mercury, patron of merchants and thieves.
Mercury had other associations. He was noted for eloquence, speed, trickery and magic. In addition to shopkeeping and thievery, he was associated with roads and boundaries. Because of his speed, he carried messages for the other gods and acted as a psychopomp, a supernatural being who guides the newly dead to the underworld.
Words coined according to Mercury’s various attributes have enriched our vocabulary.
The planet Mercury was so named because it moves fastest of all the planets around the sun. The metal mercury, also known as quicksilver, flows quickly at room temperature.
The adjective mercurial refers to the supposed qualities of people born under the planet Mercury: eloquence, ingenuity, and aptitude for commerce. Mercurial people are volatile, sprightly, and ready-witted. I don’t know if Robin Williams was born under Mercury, but he certainly possessed a mercurial personality.
As with most ancient gods, cultural currents resulted in a conflation of similar deities. The Greek version of Mercury was Hermes. They became associated with Thoth—the Egyptian god of writing, magic, and wisdom. The result was the hybrid Hermes Trismegistus, “Hermes thrice greatest.” In this triple form, Mercury was regarded as the author of all mysterious doctrines, especially of the secrets of alchemy.
The mysterious wisdom of Hermes Trismegistus was closely guarded by its practitioners, giving us the word hermetic: “airtight” or “impervious to outside influences.” It can be used literally to refer to a physical object with an airtight seal, or figuratively, to refer to a closed society, as in an article about a genre of radio announcers:
. . . with few exceptions classical announcers exist in hermetic bubbles, known only to their flocks, ignored by their peers.
The adverb hermetically is also used both literally and figuratively:
By hermetically sealing microsystems and protecting them from harmful environmental influences, their reliability and lifetime can be significantly increased.
[Pedestrians engaged with electronic devices] are hermetically sealed off from one another, not taking in the air or the stupendous buildings or the sky or just the miracle of confronting the earth as it is.
Some other words that derive from the name Hermes are herm, hermaphrodite, hermeneutics, and the female name Hermione.
A herm is an ancient boundary marker in the form of a squared pillar that often had the carved head of Hermes on the top.
The word hermaphrodite combines the names Hermes and Aphrodite. According to the version of the myth in Ovid, Hermaphroditus was a handsome youth, son of Hermes and Aphrodite. In a switch from the usual god-rapes-nymph story, Hermaphroditus was assaulted by the naiad Salmacis as he bathed naked in a spring. While her victim struggled to free himself, Salmacis prayed the gods would unite them forever. I suspect she just wanted the poor man to become a willing lover, but the gods took her literally and combined them into one bisexual body. In science, hermaphrodites are plants or animals for which it is normal for both male and female reproductive parts to exist on the same individual.
Hermeneutics is the branch of knowledge dealing with interpretation, especially of the Bible or literary texts.
Hermione is the feminine of Hermes. The name has acquired a new popularity, thanks to the character Hermione Granger in the J. K. Rowling books. Before that Hermione entered the literary scene, I was familiar with the name as a character in Shakespeare’s The Winter’s Tale and as the name of the actress Hermione Gingold. If you’ve watched the film The Music Man, you’ll probably remember Hermione Gingold as the mayor’s wife, admonishing her husband to mind his “phraseology.”