The Etymon Code
By WILLIAM SAFIRE

The Da Vinci Code by Dan Brown, the latest twist on the quest for the Holy Grail, has been a best-selling novel for the past six months. More than 2.6 million copies of this exciting yarn (multidimensional plot, unidimensional characters) are in print, and the paperback is yet to come. I interpret this fiction success as evidence of the public hunger for etymology.

That's because the author is fascinated with the origins of words. Here is a review of his rooting into roots.

''Nowadays,'' Brown writes, ''the term pagan had become almost synonymous with devil worship -- a gross misconception. The word's roots actually reached back to the Latin paganus, meaning country-dwellers. 'Pagans' were literally unindoctrinated country folk who clung to the old, rural religions of nature worship.''

The Oxford English Dictionary disagrees: ''The explanation of Latin paganus in the sense 'non-Christian, heathen,' as arising out of that of 'villager, rustic' (supposedly indicating the fact that the ancient idolatry lingered on in the rural villages and hamlets after Christianity had been generally accepted in the towns and cities of the Roman Empire . . . ) has been shown to be chronologically and historically untenable.'' The O.E.D. then sternly gives its evidence of early usage.

''In fact,'' Brown continues, ''so strong was the church's fear of those who lived in the rural villes that the word for 'villager' -- vilain -- came to mean a wicked soul.''

He's on solider ground there. The Latin villa means ''country house, farm,'' and Merriam-Webster tracks villain from a feudal peasant to a boor to a scoundrel and on to a character in a story who opposes the hero. But villagers did not become villains because the church feared them; more likely, it was just that the lords of the manor looked down on the lower classes and equated their coarse manners with loose morals.

In having a character discuss Leonardo Da Vinci's sexuality, Brown writes that he ''considered offering an etymological sidebar about the word hermaphrodite and its ties to Hermes and Aphrodite, but something told him it would be lost on this crowd.''

Not the crowd that reads this column. We all know that Hermes and Aphrodite (Mercury and Venus) named their son by amalgamating their names: Hermaphroditus. When this handsome lad swam in the stream of the nymph Salmacis after rejecting her advances, she prayed that they never be separated and -- presto! -- combined with him, thereby combining male and female characteristics and leading to the coinage of hermaphrodite. The novelist Brown has that right.

''Few Christians who gazed upon 'the crucifix' realized their symbol's violent history was reflected in its very name: 'cross' and 'crucifix' came from the Latin verb cruciare -- to torture.''

That's correct as deeply as it goes. When we track excruciating back to its painful origins, we find cruciare, ''to crucify, torture on a cross,'' and finally to the architectural, pre-painful crux, ''cross,'' or ''a perpendicular beam supporting a horizontal beam.''

Now to the root of sub rosa. The rose is a key symbol in Brown's plot. His hero says: ''The Romans hung a rose over meetings to indicate the meeting was confidential. Attendees understood that whatever was said under the rose -- or sub rosa -- had to remain a secret.''

I don't know why the novelist attributes it to the Romans. Earliest citation is in Henry VIII's 1546 State Papers, which in modern English reads, ''The said questions were asked with license, and should remain under the rose . . . no more to be rehearsed.''

In the 1960 ''Folklore and Symbolism of Flowers, Plants and Trees,'' Ernst and Johanna Lehner tell how Aphrodite (you remember Hermes's girlfriend) presented a rose to her son, Eros, god of love: ''When Eros in turn gave the rose to Harpocrates, the deity of silence, to induce him to conceal the weaknesses of the gods, the rose became the emblem of silence and secrecy. In ancient times a rose was attached to the ceiling of council chambers as an indication that everybody present was sworn to secrecy, sub rosa -- under the rose.''

That uncited reference to ''ancient times'' gives a tenuous basis to Brown's use of the symbol by Romans. But it also explains something far afield: I always presumed that in the Marx Brothers comedies, the mute Harpo was so named because he played the harp. But could it be that the comic geniuses selected that name from Harpocrates, god of silence?