WORD HISTORY: Oscillate

The rather dry word oscillate may become a bit less dry when we learn its story. It is possible that it goes back to the Latin word oscillum, a diminutive of os, "mouth," meaning "small mouth." In a passage in the Georgics, Virgil applies the word to a small mask of Bacchus hung from trees to move back and forth in the breeze. From this word oscillum may have come another word oscillum, meaning "something, such as a swing, that moves up and down or back and forth." And this oscillum was the source of the verb oscillare, "to ride in a swing," and the noun (from the verb) oscillatio, "the action of swinging or oscillating." The words have given us, respectively, our verb oscillate, first recorded in 1726, and our noun oscillation, first recorded in 1658. The next time one sees something oscillating, one might think of that small mask of Bacchus swinging from a pine tree in the Roman countryside.